I was at the eBay developers conference showing some proof of concept prototypes of new mobile applications, and I found that hardly anyone knew that eBay already has a WAP based mobile version of the site. It loads in seconds on any phone that has any kind of web browser, but there is no automatic redirect from the main eBay site. You should bookmark this on your phone's web browser:
You can also use this site to backend other mobile applications. If your own code helps a user find an item on eBay then you can form a URL that contains the item id and go directly into the official eBay WAP based site. It handles user login, MyEbay, watchlists etc. The main problem with the wap site is that the search functionality is too simplistic. The prototypes we were showing (no, you can't access them, you should have been there...) are aimed at fixing the finding experience.