[pgbovine]

research labs typically only hire Ph.D. students as interns, not master's students. an alternative choice might be start-ups who have a need for machine learning (e.g., collaborative filtering for e-commerce). i can't imagine why they would turn down a competent summer intern who didn't ask for equity. perhaps ask around for YC companies who are hiring interns.

[ephermata]

This is true, but there are plenty of other teams within Microsoft (or Yahoo or Google) that do applied machine learning. You probably won't end up with a publication in a peer-reviewed conference, but you will learn about the state of the art. Of course if the goal is improving your CV for application to a PhD program, that may not help much.

[imurray]

http://research.microsoft.com/en-us/jobs/intern/faq.aspx

The majority of our interns are PhD candidates, however, we also accept some master’s students who demonstrated a serious interest in research.

Point taken. The poster needs to decide how academic research focussed they are.