Yes there is a tour co. in Hyannis. Also, there are island tours in both Nantucket and Martha's Vineyard. Also, contact both the Hyannis Chamber of Commerce (www.hyannischamber.com) and the Cape Cod Chamber in Hyannis.
The Cape Cod Times can be read via www.capecodonline.com too.
Also check out www.CapeCodExploresGuide.com