Yup! Exact problem, it drove me insane...try writing a paper where every second you hear a squeak...not so apparent in an office, SUPER apparent at home where it's quiet.
Anyways long story short, I took it to Apple (it was within the 14 days) and the guy basically said sometimes the keyboards aren't aligned perfectly and there is a small metal pin that is out of alignment.
Took it in the back, less than 10minutes later I had a non-squeaking SPACEBAR.
Hope that helps. I don't think the "being out of the 14 day" period is a big deal, it's a manufacturing problem so you're covered. Take it in, be nice, explain the problem and they should help.
