Personally, I wouldn't try that! Unless you have a day or two to waste in case serious problems arise and you want to go back or sumthin;)
dat's my 'pinion.
I agree with Souza. Remember Murphy's Law... "what can go wrong, will go wrong" at the worst possible moment and you sure don't need that to happen in the middle of a project. XP can wait a couple or weeks more.
Don't ever upgrade in the middle of a project. This includes upgrading Vegas (unless a bug in an earlier version prevents you from proceeding). I also would not schedule any projects for at least a day or two until you've fully tested your computer after the upgrade.
Also don't upgrade from ME to XP, you're best to wipe out your hard drive and do a clean install of XP. ME can leave a lot of crap behind that can screw up your system, it's best to start from scratch when upgrading an operating system (unless you're on a mac).
I agree with all the above. Don't upgrade in the middle of a project. When you're done, back up all your data files, then reformat your c: drive and install XP from scratch. Then reinstall your apps and copy the data back. It might seem like a hassle when XP gives you the option of installing directly over Win98, but anything less is a false economy - I tried it, and ended up reinstalling anyway because of stability issues. Plus, a reinstall always gives you the opportunity to get rid of all the crap that has accumulated...