NASA offers paid undergraduate and graduate level internships in a wide variety of disciplines. Over 200 internships are available. The deadline is March 1st, but offers may begin going out as early as Feb. 2nd. Visit http://intern.nasa.gov to apply for up to 15 opportunities with a single application.
NSF offers a wide variety of paid summer research experiences for undergraduates. To search over 600 programs, please visit: http://www.pathwaystoscience.org/undergrads.asp
For summer research specifically in ocean sciences:
For summer research specifically in engineering:
For mentoring and professional development support, please take a look at AGEP alliances: