Make sure you get that taken care of as soon as you can. I think it is probably a belt. There is an interval at which those should be replaced. I don't remeber what it is, but you can find out. Anyways, it once happened to me that my bad battery was making my alternator work too hard, which therefore resulted in more heat, which in turn expanded the drive belt, making it loose and squeaky; the same belt drives teh water pump, so my radiator would come close to overheating wuite often. At one point all of this blew the alternator relay, forcing me to stop driving for a while. This entire process took approximately one year. I did not know everything that was going one, until I replaced my alternator relay, then a new alternator and a new battery (I had already put in a new battery before, but it was worked too hard because the alternator was bad) and did some retospect analysis.
* NOTE: I knew nothing about cars pretty much at that time
All of this to say: do not think that just because it is a little squeak it could not be a real pain. Treat it early and you should be alright.