I noticed my front wheel was making a high pitched chirping noise a couple blocks from my house. It wasn't dependent on the brakes but on the speed of the rotation, I think. When slowing to a creep, the sound became a loud screeching. By the time I made it back to home, the noise disappeared.
I did exchange my own wheels a couple of weekends ago--just in time for the two inches of STL snow and a very scary ride to work. Hopefully the noise was not related to something I just screwed up?