[deliriousga]

Most likely a spring cover or A-arm bushing. The easy one is to check A-arm your bushings to see if they're worn out. If not, look at there the springs meet the shocks (not sure what the top and bottom covers on the springs are called) and see if it looks worn.

You can have someone bounce the front and/or rear while you're next to the wheels and see if you can find it. If there's nobody around to help, you can jack it up, then put another jack under the tire and lift it up and down to see if you can make it squeak.