From a rep at Yahoo! Research:

Yahoo! Research Berkeley, is looking for a select few summer interns - PhD, Masters and undergrads. We have an exciting setup - working on advanced prototypes and research problems with enough independence to conduct interesting research, yet with close ties to Yahoo product groups to make this research grounded in real-world needs, and have some real-world impact. Our interests have focused around media - photos and video - with mobile and location-aware systems playing a significant role, as well. You can read more about the lab at http://whyrb.com .

Note that, unlike other internships, you will be able - and encouraged - to write academic papers about your work.

We are hiring interns from several different fields and disciplines (read: forward to your friends), including HCI, Information Retrieval, Algorithms, and more. You can further details about the intern positions and requirements at http://yahooresearchberkeley.com/blog/intern-job-desc/

To apply, send your CV to yrb-interns@yahoo-inc.com . Do it ASAP, as we will be sending offers out very soon.

Finally, you should definitely check out http://careers.yahoo.com/internships.html for more opportunities with Yahoo! and Yahoo! Research, other than the Berkeley lab.