Jack your car up in the front and get a can of good industrial lubricant found at auto part stores. You can use WD40, but it doesn't last long. Anyways, squirt the lubricant into your control arm bushings, sway bar bushings, tire rods etc. Basically anything that moves as your drive has some sort of bushing. Be sure to squirt the lubricant into the cracks beside the mating surface of the bushing and part being lubricated. This will get the lube down into the bushing and onto the shaft that they move on. Bushings dry out naturally, and when it rains it lubricates those bushings and makes the squeak go away temprarily. I lube mine everytime I change my oil.
1994 GT Automatic
Edelbrock Performer RPM intake, Motorsport "E" Cam, GT-40 Iron heads(ported), BBK shorty headers, Hollowed Cats, Flowmaster Mufflers, Built AOD-E, 2500 Stall, Trans
-Go Shift Kit, 4.10 gears, MSD 6AL, Accell Coil, MSD Super Conductor plug wires, Smog pump eliminator (all emissions removed), K&N, 24# injectors, EEC-Tuner, 75mm MAF, 70mm Throttle Body, and Oh Yeah 150hp NOS