First buy a tuner and make sure you can tune the thing otherwise it will sound awful! Then dig out a couple of your favourite tracks on CD and try to play along, you know pick the riff out on one string or something, AC/DC is good for this cos its not too complicated! At least when you start to learn bar chords from your DVD's you'll know a couple of basic tunes and in the meantime you get an idea how the guitar works by playing along with Angus!
I think finding a guitar tutor that will teach what you want to learn - rather than what they think you should know - is the fastest way to get there.
(I taught myself and I'm sure lessons would've helped and probably still would!)
Anyway good luck, its worth it!!
I stuck a few more tracks on our site before christmas if you want a listen:
http://www.theadhesiveexperience.co.uk/Music.html