Basically the minimum transfer time at Schiphol is 40 minutes however it is a large busy airport and the question about making your connection depends on a few different factors. The airport is built around a one terminal design so although the building is designated as arrivals and departures 1 until 4 these are not actually separate buildings as in the case of say London Heathrow or JFK, you can easily walk from one end of the airport to the other although this could take nearly 30 minutes.
It is however divided into Schengen and Non Schengen areas. See the general information about the airport below for more about the zones. If you are travelling Schengen to Schengen or Non Schengen to Non Schengen then you will not cross any kind of border and hence there will be no immigration checks. If your flight arrives from say the far east or even one of the EU countries not in the Schengen area e.g. the UK or Republic of Ireland, and departs for say the USA, then you will only be subjected to security screening at the departure gate.
Since you are recommended to be at the departure gate for intercontinental flights at least an hour prior to departure then in theory that there should be at least 1hr15mins between your scheduled inbound arrival time and scheduled outbound flight. Airlines do however sell shorter connections than this but anything less than this will make it very tight.
If you are arriving from Non Schengen e.g. from Buenos Aires and taking a flight to say Rome then you will have to cross the Schengen border at the head of Pier D. In the early morning lots of flights can arrive from the far east and also transatlantic night flights. This can make this transfer point very busy so be prepared for a long wait. At this transfer point there are passport control desks and security screening. There is also a fast-track line to the left for short connection time flights. If your flight has less than 50 minutes connection time then check the screen above the marked lane to see if you can use this lane. Note this does not mean you can wander around the airport until you have less than 50 minutes to your next flight, only specific flights are eligible. The fast-track is also accessible for all passengers going to Paris on KL-AF and for most business/first class passengers.
From this point to the furthest away gates on Piers B & C can take 15 to 20 minutes walking time so if your flight is about to leave do not hang around.
Conversely if you were flying Rome to Buenos Aires then you would only encounter passport control at this point. As described above security for Non Schengen departures is done at the gate. Again though take into account minimum times you need to be at the gate and walking times. From this point to say the furthest gate on pier G or E can be 20 minutes easily.
Probably the easiest connection is Schengen to Schengen. You will encounter neither immigration or any security checks as you are deemed to have been screened at another trusted airport within the Schengen zone and you should easily make such a connection within 40 minutes.
All of the above relates to passengers who have through ticketing with one airline or alliance e.g. KLM to Delta, or where airlines have interline agreements for checked baggage. If you have to go to a transfer desk to get an onward boarding pass then allow much more time. If you are using a budget airline and have luggage to collect and check in or you need to re-check in then you will need a minimum of three hours between flights.
Please also note that if your onward flight is on KLM Cityhopper or another airline with relatively small regional planes it may be, especially if they are using a small Fokker 100 or 70 or Embraer, that you will be busses to your aircraft. Gate D6 is a collection of gates D6a, D6b etc. where you WILL be bussed. These gates by nature close quicker than one with the aircraft actually at the gate and once the bus has gone you will be left so be aware of this. There is a similar gate for bus connections at the B-pier (Schengen).
General airport information.
Schiphol Airside
Amsterdam airport is divided into two sections; Schengen and non-Schengen. The Schengen area includes most EU countries eg France, Spain, Italy etc. http://en.wikipedia.org/wiki/Schengen... . All intercontinental flights leave from the non Schengen area which includes Piers D (although not all gates), E, F, G & H. For all these piers (apart from H but these are only used for short haul budget carriers) security checks and searches are carried out at the individual gates. Just be careful not to buy drinks or water etc. to take on the plane as these will be confiscated at security. Also note that if you are a transit passenger then do not buy liquids/gels etc. over 100ml at your originating airport as these will also be taken off you at security. The only liquids you can take through here have to be 100ml or less or have been purchased in Schiphol or in the previous 24 hours at an airport on the secure list and sealed in a security bag. See here for current details
http://www.schiphol.nl/Travellers/AtS...
If you're flying to America, you'll find that you can shop, but your purchases have to be delivered to you at the gate - you won't be able to take your amusing clog-shaped chocolates or perfume through security yourself, but this could be an advantage: less to carry.
For flights originating in Amsterdam to another Schengen country (Schengen gates are B, C, D gates above 57 and M) the security scanners are centralised after check in so you can buy whatever you like airside and take it on board.
Schiphol is a large busy airport but very well designed with lots to do & see including some genuine Rembrandts, Vermeers and other old Dutch masters from the Rijksmuseum. If you did not get the chance to see any of Amsterdam's world class museums then check it out for free between piers E & F.
For the smokers among you don't worry. There are designated smoking areas on all piers, normally in an enclosed area of one of the many cafe's and bars.
http://www.schiphol.nl/Travellers/AtS...
Airside there's mostly tourist-item and usual airport shopping, a couple of bars, a bookshop selling English-language books; a McDonalds with a small wifi work area; an ocean-themed bar and a few other small places to eat. You have access to small trolleys to push your hand-baggage about the terminal, which is a really nice touch.
If you have a long layover at the airport they have recently built a pod type hotel called the Yotel where you can rent a room in four hour stretches. Great to just chill out and get away from everyone, have a shower or just relax and watch TV or surf on your laptop. The other airside hotel, Mercure Airport Terminal, has a similar model though their minimum day room rental time is eight hours. They also offer separate showers for hire.
As a recent addition in 2011 wi-fi is now free for an hour throughout the airport. A Public library has also been added to the airport with ipads. There is a selection of Dutch and English literature.