There are two in mind that are both free or have a free version. DeepBurner is a commonly heard name while BurnOn has proven itself worthwhile on both XP and Vista alike. For BurnOn go to http://www.burnworld.com/burnoncddvd/
That one works great with Linux iso images as well as backing your drive on data dvds. For the free Linux drive tool known as GParted live for cd it's retail version is also low priced when compared to others. For DeepBurner's home page go to http://www.deepburner.com/
One thing I favor BurnOn for is the ability to create bootable cds, dvds from iso type disk images as well as burning data dvds. The full retail version is also low priced compared to some like Roxio's Easy Media Creator or Nero even. $9.95 compared to the original $99.95 for Roxio? ouch!
Quite a few programs out lack support for either burning iso images or disk images created by other programs. If you plan on running Linux at some point the distros themselves are downloaded in iso type disk images and then burned to disk. Programs like Norton Ghost or Acronis create their own type of disk image for backing up Windows drives.