I did a little research for my brother-in-law on clip-art and mp3's. Here's what I came up with: $29 Font Wingdings:
$179 Good Clip Art CD: http://www.fonthaus.com/products/clipartcds/view.cfm?sku=AR10501
$$$ Expensive Subscription: http://www.comstockcomplete.com/en/company/learn_more
The best a la carte (pay per image) site: http://creative.gettyimages.com/source/home/home.aspx
Convert from AAC to MP3: http://www.macworld.com/2004/09/secrets/septemberdigitalhub/index.php
You'll want to burn the AAC files to a disc, and then re-import them as MP3.