Socket 939 also has AMD Athlon 64 X2, the reason why I didn't mention the am2 is because it requires ddr2 ram.
If you get ddr2 ram, it's best to go with the intel core2duo build since, even the slowest of the core2duo cpu will match or beat even the best of the amd cpu
You can go here to check on some cpu comparisons.
Most of the motherboards for s939 support your parts and should be compatible. If you want to check to make sure, just post your parts.
Also, if your case is mini ATX then you will need an mini ATX motherboard. However if your case is ATX, you can get either
mini ATX or ATX.