i think partition magic can do this
but double check before you take my word for it
Acronis Disk Director Suite
Available, apparently!!!!!, via those file sharing things!!... if you get my drift
This is a good partition tweaker... I used it to increase my OS partition, which Vista will not let you do under disk management, without losing data. ALL partition software worth it's salt reccommends backing up data BEFORE fiddling with partitions
Hope this helps
Doesnt work in windows 7 apparently