I use 8.5 x 14" paper (legal size). You can print DVD case size covers on this with any printer. I get perfect size jewel case and DVD covers every time by using Microsoft Excel (although I suppose the Open Office version would work). I'll use the CD case as an example.
For the front cover/fold over insert I tweaked two cells on a spreadsheet until they were just the perfect size to fit the case when printed. Used the cell format to put a faint dotted line around those cells for a scissors and folding guide. Then you just paste in the cover art and size it to fit the cell. Text can be entered and formatted in the second cell, just remember that Alt-Enter gets you a new line in a cell and turn on Wrap Text.
For the inside cover/spines I tweaked three cells, two thin ones for the spine label using the Rotate Text in the format cell. One large cell in between for cover art, text, etc. Again, dotted lines for cutting an folding guides, you can also just paste in a scanned file and size it to fit.
I don't have the DVD version tweaked in yet but the CD version is attached.
CDCOVERS.zip (2.34 KB)