The general rule with AMD phenoms is if it ends in a 0 DDR2. If it ends in a 5, it swings both ways DDR2 and DDR3.
Here's the most important tip. Every motherboard manufacture has a website where they list specific CPU compatibility for their motherboards. Always, always, always, I can not stress this enough, check against their list. So much heartache can be avoided this way (...but I didn't know it only support 95 watt CPUs, and DDR2, or there was no BIOS update for 6 cores--it fits in the socket though....)