HELP! With this chirping/squealing noise! B4 I snap!!!

Whenever I'm going less than about 25 mph, with the car in gear, I'm getting a chirping/squealing noise, seemingly from the rear of the car. I also get this sound when driving on bumpy road at low speeds. The car doesn't appear to make the noise unless it is warmed up. Could this be the bushings? Or am I looking at an axle bearing or something in the diff? Any suggestions or past experiences are appreciated.

Thanks,
Derek

Thanks for the tip....now that I think about it, I could see it being U-joints as the sound leaves with higher engine speed and faster car speed (more noise = harder to hear).

I'll check that out.