There is a lot of information available online about Brighton, and a great place to begin searching is on the Official City Webpage. On this site there is general information about everything one needs to know about this beautiful seaside city. From accommodation options, dining recommendations and attractions, to information about festivals and events and a map.
In the event of legal problems during a visit to Brighton, visit the Brighton Police website. There is great information on this site, including useful phone numbers and addresses.
Another useful site is the city council site as this give you general information about the services on offer including the libraries and the parks, as well as information on new developments planned in Brighton & Hove.
The British government offers foreign-specific travel advice for visitors to the UK, and is available at Travel Advice.
A complete list of foreign embassies in the UK, including addresses and phone numbers, can be found at Foreign Embassies List. Note that most of the embassies are located in London, which is just under an hour away from Brighton by car.
If you plan to use Brighton as a base for exploring the county of Sussex then the VisitSussex site will be useful to you