A few more independant record labels who have some free mp3s on their websites:
Sub Pop Records (free music availible includes songs by The Thermals, Flight of the Conchords and The Postal Service)
Matador Records (free music availible includes songs by Mogwai and Guided by Voices)
also there’s RCRD LBL, which features about 150 or so free, legal MP3s by several notable indie rock bands like Beach House, Why? and Late of the Pier. All music availible on this site is availible with permission from the musicians and/or the record label although not all artists featured on the site have mp3s availible to download, only streaming, but most do.