I don't know of any free backup software for Vista that I would call "good". There are a number of members here who are users of Norton Ghost from Symantec, Vista compatible since v12 and now at v14. You can get the dry facts about it from Symantec, but a far more friendly write up at this site:
http://ghost.radified.com/

Even there, you will find a list of "Ghost alternatives" -- other programs that do backups. If you must have free, try DriveImage XML which forum moderator SarahJames has worked into a backups solution and HTG blogger Mysticgeek writes about with pictures:

http://www.howtogeek.com/forum.....p-solution
http://blogs.howtogeek.com/mys.....k-imaging/

hey,
drive img made the data use twice the space it actually does. suggestions?