Avery Office Products, the purveyor of labels, blank business cards, binder dividers, greeting cards, and iron-on t-shirt transfers, has released a free application called Design Pro for Mac.
This software was demoed at Macworld Expo in January and is now available for download (registration required) from the Avery website. Design Pro contains over 2,000 clip art and photo images, as well as over 1,300 pre-designed templates for various projects. It is integrated with iPhoto as well, so you can use all of your own photos to create CD/DVD labels, birthday cards, and other fun projects. If you're burning your own music CDs, Design Pro can grab playlist or tune information from iTunes, and it's also able to use your Address Book for doing mail merges.
Avery Design Pro for Mac requires Mac OS X 10.4 or 10.5. Be aware - the download is 262MB in size!