im looking to buy a new CPU and i see not all of them come with cooling devices, would it be ok to use the fan i have already or would it possibly not fit?
Well your board is socket 939, so you would have to get a 939 processor it fit it. So yes the cooler would fit, but if the processor is bigger and runs hotter, will it cool good enough is the question.
It would physically fit, but like StrangleHold said, it might not thermally match your new CPU. There are lots of socket 939 hsf out there, if your old hsf won't cut it, it wouldn't be too hard to buy a new one.
AM2 and AM2+ are the same socket type, the cpus are forwards compatible, but not back (AM2+ wont work in AM2)..
some coolers will fit, some wont.
it really depends on you're cooler and board.