Well, let's see, Swirler, I haven't had a chance to really get into 4th edition just yet, but I have been told by several of the Pub patrns that the rules-set is much more streamlined than the previous 3 versions. Of course, that was the main goal of having a new edition, so apparently FP actually managed it. The timeline has also been shifted ahead by 7 years, so alot of the recent (read last 20 yers of game-time) is going to be more or less ot the window for suplimental material. Normal history, that is from 1980 - 2050 is still consistant. Of course they didn't toss out all of the history generated by the novels or modules, but you will have to really check sources for things like current corporation drek and just bout everything having to do with the matrix now that it's wireless.
Unfortunately, that's really all I know about 4th edition. I've been between runner groups in RL for about 2 years now, so bummer for me. Now if you have a 3rd edition question, I'm your elf. Well, me and Retread and ROOTless. More Retread and ROOTless, actually. In fact, you may just want to IM them.

Gabriel
PS - Welcome to the Pub, chummer.