I work for a small business that does a lot of commerce via eBay. Right now, we have a pretty large database (in FileMaker), and our current method for getting newly-entered items from the database to eBay involves entering them manually, line-by-line, through a browser window into Auctiva. This is an extremely time-consuming process, and I've been tasked with automating it, if possible I've already written a good bit of code in Ruby to parse tab-delimited FileMaker exports into pretty much whatever I want, so I was wondering if there was some way to upload static HTML directly into an eBay listing. If so, I could just snag a spiffy HTML template from oswd, modify it, and modify the code I've already written to handle injecting the pertinent info directly into the document, then just upload that.
If you can do whatever with the product data, and have all the data necessary to make a listing, you can use the eBay API.
http://developer.ebay.com/products/trading/
has a HTTP POST based submission handler so you can use any http client you want (Net::HTTP, HTTP party, Curb etc) and post your listings that way.