Collectibles Sales Data
Slightly off topic, but still of some relevance... Auctionbytes recently posted an article on a website called Smart Collector. This site analyzes up to 120 days of eBay sales data to help you find pricing and other information about your item. I played around a little with this site and it seems like both a lot of fun and of some value to the lay antiquer and dealer alike. Registration is required but the service is free.