What sort of squeak is it? Does it sound like... - metal on metal? - cold brake squeal? - something else?
Well you may have glazed the rear brake pads. If thats the case then remove the rear pads and scuff them up with some nice coarse sand paper. Aside from that, there are a few products on the market that claim to stop brake squeal... not sure how effective they are or chemically how they work.
Dang I was a sleep when I made that post. I seem to be doing that a ...... <!-- s:zzz: --><img src="{SMILIES_PATH}/icon_sleeping.gif" alt=":zzz:" title="Sleeping" /><!-- s:zzz: -->