Tillman over at Anandtech has whipped up a pretty hefty SocketA & Socket370 Heatsink Comparison. Pretty good stuff, all the current big players are there, worth checking out. You can compare results with our similar recent comparo.
Sabretooth points out new Promise FastTrack66 drivers for Linux. He thinks they'll work in RedHat 7, but isn't sure. So if it kills your system, no forming an angry mob outside his place like last time.