Depends what you want really.
There are pre-cut sheets for CD covers, front back and for all designs of jewel cases. There are kits that come with it all in including software but they work out fairly expensive.
Nero 5 has software to design covers but the designs are shite although, its good for text.
Best way is to make a template yourself and save it then use Photoshop or other software or even Microsoft Word is okay with a lot of imagination importing pictures and such. Print it on quality paper and then cut it out or use a mini guillotine like I do.
Many many options.