I've just run my second use of EASEUS free version 3.5 and find it amazing in it's simplicity and speed. The first use on my main machine, XP Pro with 5 partitions, I needed to increase the size of the main "C" Windows partition. Nervously I performed the resize on the "D" partition and the "C" partition adding 3GBs to "C". Amazing speed and performance. Perfect result.
My second use on my test machine, I just finished expanding a Vista OS active partition while reducing a Windows 7 RC1 install on "D". Again, terrific performance and that's with an OS that isn't even ready for prime time yet.
This isn't for the novice in some ways since the one reboot may take you to the Safe Mode boot but really, with common sense choices this is the best Partition Manager I've ever used and I've paid for Partition Magic and others over the years.
http://www.partition-tool.com/