The most important thing you could ever buy is Fenner's "the concientious marine aquarist". This tells you everything you need to know. Also, do a lot of research on this website. It's hard for someone to tell you in a thread everything you need to know about starting up... you may miss some valuable information.
Also, for the fish, you should definately buy "the pocket handguide to marine fish". It is the best book on fish there is. It tells you everything about fish you need to know, such as: the size tank they need, what they eat, reef compatibility, other fish compatibility, and much much more. This is the book i used to plan my tank, and i'm so glad i got it.
If you read those books, and still have questions, this is the place to be, but the first thing you shoul do is get the marine aquarist, it's a life saver.
Welcome to SWF.com, and good luck with everything!!!
Jenn