Dubstepforum.com

http://www.pandora.com/

Im sure a few already know about this but for those that dont be sure to check it out. It's like internet radio catered towards you're needs. type in an artists and it spits out other artists that are similar in style and that you may like.
bare in mind it wasn't made in an alley so don't expect too many deep deep underground artists coming up but I've been surprised a few times.

very handy indeed

I love this site... great for finding new music and for giving the fellow office-folk a break from my taste in electronic music

Burial's on there...

pandoras awesome! ive been introduced to so many artists from there its great for reggea!