Go to http://tomshardware.com and http://anandtech.com and read the details of each so you can choose wisely.
Remember that only the socket 939's basic CPU's have a dual channel MCH. For the others, only the very expensive FX versions have dual channel.
Pretty sure that http://www.newegg.com has a socket 939 in your price range.
I'm thinking about building a new desktop from scratch since i need a new comp for college soon. Its been a few years since I built my last one and so I really need some advice on hardware parts and compatibility. Right now I'm looking for a motherboard that supports AMD 64 processors, preferable 939 but 700s okay as well. My price range for the mother board is <$150. Thx.