Maintenance

Car maintenance that is. I've become fairly adept at maintaining my car on my own. I can change the air filter, the battery, the headlights, taillights and windshield wiper blades by myself. I could even change a flat tire if I needed to, but on the side of the road I would probably still use USAA. I would like to learn to change my own oil, but until I can find someone to teach me, I'll stick with paying professionals to do that.
Two years ago, my stepdad and I replaced the belts in my car. A year and a half ago, I learned how to change my own brakes and shocks when they needed to be replaced and I didn't want to spend the money to pay a professional to do it. My stepdad patiently stood over my shoulder and told me what to do while I did the work and then checked just to make sure all the bolts were tight enough before I drove off. Six months after that, I replaced my own O2 sensor so that my car would pass inspection. It almost killed me last February when I needed a transmission overhaul, my clutch replaced and my a/c fixed because those were things I couldn't do myself and it ended up costing me over $3000 - OUCH!
Well, now, those same belts that were replaced 2 years ago are squealing again at fairly regular intervals, but only when the a/c is turned on. I checked them myself this morning and they look ok to me - no cracks visible to my eye and they didn't look loose - but still they squeal. Problem is, I don't really have the money to replace them right now. Not that they are terribly expensive, but to a dried up pocketbook, just about anything is expensive. I'm wondering if there is anything I could do, possibly lube them, that would help with the squealing. Does anyone out there have any ideas or suggestions? It would be a great help...
By the way, the first week of school went really well - only 35 more to go!