This free (Alex accepts PayPal donations) ISO Burner/recorder works pretty well on Vista and got both 32 and 64-bit versions. Quote from his site:

ISO Recorder is a tool (power toy) ...snip...  to burn CD and DVD images (DVD support is only available on Windows Vista), copy disks, make images of the existing data CDs and DVDs and create ISO images from a content of a disk folder.

Insert blank DVD, right click on an .iso file and select "open with ISO Recorder" and a few clicks later you got your DVD burned. Just the way I like it.