I've finally found time to play BG after owning the boxset of 4 DVDs for several months. While I think its worth reading all of the documentation eventually, I've never played these games before and I just want to get started. Which parts would you reccommend I read before I start?

Depends, do you know much about Dungeons and Dragons? You might want to consider checking up on those rules before starting. I'd read the manual as well, and if your game didn't come with it, look in the program files for it. =)

Never played an AD&D game before, I didn't know that knowing the rules was that relevant...so I should get to know them? What else?

It might be useful, the game is pretty simple to figure out when they begin to teach you the basics and such, but if you really want to unlock some of the gameplay elements you might want to read up on it. It's not necessary though.

After you start, I would recomend talking to all of the Green-robed tutors, and talking to everyone in Candlekeep. You'll get some great advice on combat with a party, general game mechanics, and some experience to boot!