Garage Sale for the mac is a full featured eBay auction manager for the Mac. It allows you to create very slick professional looking auctions, monitor, and keep track of your transactions.
Most of my time in this program will be spent in the Template section. This is where you create auction listings. At the top you put in your title and add your images. You can drag or drop images in - or click the + button and import them directly from your camera, iphoto, or your webcam. Once they are there you can crop and adjust them. Garage sale will resize them appropriately and upload them to ebay or the FTP server of your choice. Then you type in your description below that. This is a word processor like screen that is easy to use. On the side are all your auction options - what section, starting bid, buy it now, shipping settings, etc.
When you are done you can select the look of your auction by clicking preview at the top. Here you can select the style and the way you want your images placed. If you are happy with it you just click start auction at the top. It will give you what the listing fee will be and you confirm it - Garage Sale does the rest.
They regularly update the program to add features and new listing designs. I have contacted support before and they were quick to respond with a fix. An excellent program all around and well worth the price.