It may be effective or it may not be to sell excess inventory on eBay, depending on the item and the price and who happens to be looking (and what they're looking for) when you list your items. It's impossible to make a blanket statement of whether it will work or not, but I can tell you there are some folks who do quite well selling excess inventory there.
As to linking to your site, to my understanding you can't include "offsite" links in product listings. They used to allow you to link to other commercial sites on your "about me" page, but I believe they're no longer allowing that, either. They really don't want you to promote any "off eBay" website through eBay. You can try it if you think you can get away with it, but if you do, don't be surprised if you wake up one morning to find your account disabled.
Diane Aull - NineYards.com
: Helping Businesses Do Business Online
Whether you think you can, or that you can't, you are usually right.