Look at Symantec's product called "Backup Exec System Recovery Server Edition"
(BESR, for short) Here's a link:
http://www.symantec.com/business/backup-exec-system-recovery-server-editionIt will image your servers live (including Exchange, SQL and everything else) and will allow you to scedule when it does the imaging as well as help you keep a certain number of images. There's a nice, fully featured trial version that you can download to try out. Another added bonus is that you can retore your images to dissimilar hardare or virtual environments. It is a GREAT product.