eBay has a neat new way to promote your items for free. Users can take any item listed on the auction service and widgetize it using a really simple editor. There are three options to choose from: single item, multiple item, and search. The multiple items widget has a scrolling display of item images, and is good for Powersellers, or anyone who is selling a few things at a time. What's great is that you don't even need to sign in to eBay to make one, just an item number.
When you're done creating a widget, you can embed it in a number of blogging services and social networks like MySpace, Blogger, and Wordpress. I find it quite interesting MySpace is letting users embed auctions to their profile pages, especially after the whole Photobucket ordeal a few weeks ago; although in this case, it's not corporate advertising.
My favorite, and the one I've embedded below, is the single item widget which features a real-time countdown until the end of the auction. There's also a thumbnail viewer for any pictures, and status information like the bid and view counts. The one thing missing is a way to bid on the item without leaving the page, something I think would do well given a built-in login option.