Official Website for Dubai Marina, on Emaar's (Developer) website:
http://www.emaar.com/Developments/DubaiMarina/
B.D.'s photo blog on Dubai Marina:
http://marinaphotos.blogspot.com/
The official website for Dubai Marina, Park Island, Marina Quays and Marina Promenade:
http://www.dubaimarina.ae/
Wikipedia's entry on Dubai Marina, has all the important facts and figures:
http://en.wikipedia.org/wiki/Dubai_Marina
Real Estate website, buying Dubai Marina property at Gowealthy.com:
http://gowealthy.com/realestate/uae/dubai/dubaimarina.asp