a) Welcome aboard!
b) The Welcome to the Shadows forum is for Play-by-Post gaming, you probably want to check the Shadowrun one. Don't be afraid to ask, and don't be afraid of us.
c) Basic book:
Shadowrun Third Edition (if you live in the US, you can get it from most online retailers).
d)
Official website. Lots of good stuff in there.
e) If you want to start easy after the Big Black Book, go for
First Run. It has a few easy adventures that gradually increase the game's complexity. Just remember to play
Food Fight in Tarantino style.
f)
New Seattle gives you the default setting circa 2060. If you want to, you can always try to get your hands on the original
Seattle sourcebook (obsolete, but chock full of ideas).
g) There are several thematic sourcebooks (
Magic in the Shadows, Man & Machine, Cannon Companion, Rigger 3 Revised, Matrix). Go for them, but only after you're comfortable with the game and wish to expand on a certain aspect of it.
h) Gamemaster tools:
SR3 Gamemaster Screen includes a book with stats for most SR critters.
Shadowrun Companion has additional stuff for players and GMs that you'll find very useful.
Corporate Download gives you tons of information on the powers-that-be in the Sixth World. It's incredibly good, trust me.
i) Anything else: Buy everything!
Just kidding, go slow and get the basic rules first. There are several campaign books out there, but if you want something a little like a D&D dungeon crawl, you might want to check out
Renraku Arcology: Shutdown first, then
Brainscan. Excellent, self-contained stuff happening in Seattle, with a little fun in Hong Kong to add some spice.
j) If you're planning to play before 2055: Never, ever, let your players know about Bug Spirits.
(related books:
Queen Euphoria, Universal Brotherhood, Double Exposure, Bug City... the first gives you a taste of them, the second makes you run away in the night screaming, the third one is a great adventure and the fourth one is the official sourcebook for Chicago
)
k) There's a lot of good stuff like
Sprawl Survival Guide, the continental sourcebook
Shadows of North America (watch out for Shadows of Europe in May) and
Dragons of the Sixth World.
However, these are 2061 and onwards, with plenty of things happenning between them and the BBB (like
Year of the Comet). Like I said, take it easy at first (though I'd take
SoNA just to give you a better idea of the setting).
l) Don't run away from me, I don't bite... much.