@DaaZ worked great for me once, i sold a LLLL.com
Realize “auction” format is severely limiting? John is right. Try only the best names for auctions.
Some people swear by Sedo auctions, never tried them.
I never had success with GD auctions, maybe you will.
i would advice against Flippa, specialize developed sites and also i always have bad time with Flippa.
I have heard some success stories for eBay, but eBay does not specialize in selling domains; although ebay specializes in auctioning off the strangest things! GL!