Any bands like Mgmt, Ratatat, Dream Tribes, Pion Pit, Animal Collective, Cat Power, Of Montreal, Ok Go?

Go on to www.last.fm and type in the bands you already know and like, then on each band profile page it has a 'similar artists' section which you can look through, then you can click on the other bands and listen to some tracks by them. I found a lot of new music through this site.