C.R.O.W. Externship for natural science students
http://www.crowclinic.org/externship.cfm
Good for animal lovers interested in wildlife rehabilitation. Internship and fellowship both come with shared housing. Fellowship only recieves small stipend.

Environmental Law Institute, Research Intern
http://www2.eli.org/about/employment/researchintern.htm
Transportation stipend only.

Media Matters for America
http://mediamatters.org/about_us/jobs/
Progressive media outlet. Internships are paid and applications accepted on a rolling basis.