I have a Pentium Dual Core E2200 @2.2Ghz and I will soon be upgrading to a Phenom II X3 @2.8Ghz. I was wondering if I could take the stock cooler of the Pentium and put it on the Phenom. It will be like this for maybe a couple weeks, because I need my rebates before I can buy another cooler.
That won't work for you. The E2200 stock cooler is built for the socket 775 motherboards and your Phenom II X3 will need a cooler that will fit a AM2/AM3 motherboard socket.
Won't your Phenom II X3 have a stock cooler in the RETAIL package you buy? Or are you getting just the OEM version?