You can use ntbackup to do incremental backups and schedule them to run each night. This will create a bkf file which can be taken offsite.
How you take if offsite is another story. Some people suggest USB HDD's that they take home each night and swap over in the morning, some suggest online backup, and if you have the money a tape backup. In my opinion i would go for the tape option, but if cost's came into it i would then seriously look at a NAS box with a RAID 1 setup (Mirror). Have 2 of them with the same name and swap them out each day, configure your backup to backup to the share on the NAS.
I have not used online backup before, and i don't think i ever will. I do have questions about it for people who have used it:
- How easy is it to restore data/files?
- How secure is your data, what sort of guarantee is there that the online storage company won't lose your data.
Personally i would shell out the money for tape backup, but it comes back to how much is your data worth to the company?