So far I've found gumtree to be the best, put an ad on there a week or so ago and allready had about 5 responses from people at my uni who want to get a band going or to add another guitarist.
Sadly none of it is really music I'm into, apart from an acoustic singer songwriter guy who wants a 2nd guitarist to fill out the sound a bit and play leads so I might give that a go if he's a good singer.