If you want to backup Windows Mail in Vista you can use the built-in Windows Backup, otherwise if you use another program to backup the directory C:\Users\{yourusername}\AppData\Local\Microsoft\Wi ndows Mail to another location that should allow you to restore your email in the event of a disaster. An external drive (e.g. the Seagate FreeAgent 250GB USB2.0 External Hard Drive which would be £37.99 from ebuyer.com) could be your backup destination. Alternatively you could use a CD (if it's less than 750MB), a DVD (if you have a DVD writing drive), or even backup to a another directory on the disk and then upload it to some free storage space. I've not looked into it in detail but
http://www.123-reg.co.uk/online-storage-drive/ might be worth a look.
If you want more specific help, let me know which edition of Vista you are running, what model or PC/laptop you are using and I'll come up with something a bit more precise
