I think I'm going to wait until I have 2GB of RAM until I upgrade from Windows XP to 7.
I know I lose almost all of my data though. :c
1. Put all of your data in one zip.
2. Upload it to mediafire.
3. PM/email yourself the link to the download.
4. When you have upgraded and stuff look in your emails/PM's and download the zip.
5. Then extract.
6. ????
7. Profit.
It might take ages to download and put everything in one zip, but it's worth it if you want to save all of your stuff.
NinjaEdit: Actually unless you have mediafire pro you might not be able to upload it to there. If you don't, use another file sharing site that lets you.