I frequently get news of summer internships and post-graduate programs. I'll try to keep this up to date as the year goes on.

International opporutnities

DAAD RISE: Summer Research in Germany (English language). Deadline 1/15/15

U. S. Corporate Internships

Merck: Variety of positions/deadlines

U. S. Academic/Non-Profit Internships

NSF REUThe big one. Many sites, different deadlines