Mac's don't really have a nice way to copy CDs/DVDs. If it's a non- copy-protected DVD, you could use Disk Utility, HandBrake (free non- Apple), iMovie or iDVD, DVD Imager (free, non-Apple) and jump through a bunch of hoops. A better idea may be to use MacTheRipper (http:// www.mactheripper.org/). Or you chould pay $99 and buy "Fast DVD Copy" which promises to do it in one click. Or check out DVD Copy ($49) from http://www.imtoo.com/, or DVD2one (30 euros). Another commercial options is Roxio's "Toast Titanium" ($80) or Popcorn ($50).
So, in summary:
* If its a non-copy-protected DVD, use Disk Utility. Here are some instructions:
http://creativebits.org/mac_os_x/make_a_dvd_copy_of_mac_os_x_tiger
* If not, buy one of the products above, or use MacTheRipper with a burner. See
the website.
--ravi