[nickw311]

What software is out there to legally back up Movie DVDs for OS x and also will a USB 2 or Firewire DVD Burner pretty much work seamlessly with the applications? What about iDVD? Will it work with an aftermarked burner?

Thanks

[drive-thru]

I use Mac The Ripper to copy the DVD disk and remove any region restrictions and encryption. It's a one-click operation and very easy to use.
Next I use dvd2oneX to compress the ripped DVD to 4.7GB (?) to fit on a normal DVD-R.
Finally, Roxio Popcorn Roxio Popcorn to burn the files onto a DVD-R.

This method allows you to keep the full disk menus, extras and chapters in tact if you wish - although only Mac The Ripper is free.

[drive-thru]

Forgot to answer the other part of your question...
If you are exclusively looking for an external burner, rather than an internal upgrade then most of those drives will not natively be supported by the iApps (like iDVD).
Some drives have drivers which will show the drive as a supported superdrive, take a look at http://www.xlr8yourmac.com for more info on this.
Alternatively there is an app called Patchburn which will allow pretty much any DVD burner to act as a supported superdrive.

[nickw311]

Thanks a lot for your quick replies. I will look into it more deeply once I get settled in on my new Mini.