Today Nvidia has [URL=http://www.nvidia.com/object/sysutility_1.0.html]introduced a software[/URL] that does what the creator of WCPUID [URL=http://www.h-oda.com/]H-Oda![/URL] did with "SoftFSB" years back: Allow "on the fly" clock control from within Windows. It also supports on-die thermal readings from the Athlon CPU's that supports it and also shows a host of voltages including chipset voltage.
I had a quick run with it on my [URL=http://forum.abit-usa.com/showthread.php?s=&threadid=26655]unstable[/URL] Abit NF7-S and came to the conclusion that the on-die temp reading does not work, neither the system temp... If it works better with other mainboards we will see when I [URL=http://www.aoaforums.com/forum/showthread.php?t=21474]decide[/URL] which one to buy. The reported CPU voltage was also way off however I could still change the clock without rebooting... The program is well worth a try and will hopefully reliably show all those temps and voltages in future revisions.
UPDATE: The clock control seems broken also, after a few more retries the computer hangs... Thanks Didou!