About an hour or so after playing any game on my PS3, the cooling fan starts spinning really fast and it makes the system really loud. I was wondering why this happens, and if its harming my PS3 in any way. Comments/Answers are appreciated, thanks.

It just means it's getting hot and starts to circulate air faster to cool it down, crisis averted.

yeah, like Iantus said, it's not a problem but a solution to the problem. They just turn down the fan when it's not needed so that the system is quieter.

Thanks Guys! I appreciate it.

Mine does it always after about 30 minutes of playing or even watching something through the media server.