I think when installing W7 it will give you the option to "use the entire disk" as I'm fairly sure Vista did too.
This being the case you don't need to do anything beforehand.
If you really want to get rid of partitions you can find a LiveCD for GParted or similar as an ISO and then "create disk from image file" or whatever in your favourite disk burner.
Remember to backup anything you want to keep before changing partitions - just in case.
If you change the size of the partition that Vista (or XP) is installed on, after you exit GParted and eject, reboot, allow Windows to complete any disk check that runs during its boot up.
Puppy and Ubuntu probably have GParted on the their LiveCD too - new version of Ubuntu out today.
prompt $P - Invalid drive specification - Abort, Retry, Fail? $G
prlzx on n e w n e t Max ADSL