Looking for a free/cheap backup solution on OS X for NTFS external HDD I'm looking for an incremental backup system on OS X that plays nice with USB NTFS-formatted external HDDs. I am currently using NTFS-3G to work with the HDD, but since Time Machine doesn't work with NTFS drives, I have just been manually copying files from my HDD to back it up (ugh).  

I need to use an NTFS drive because I am going back and forth between Windows machines at my school and a Mac at home. I have no permissions at my school to install any Windows software, so I am forced to find an OS X solution.
You can use Time Machine. This page tells how to enable NTFS for writing from Snow Leopard.