I went to the site this morning to check it out and it reads:
Closed for new signups
Unfortunately it has come time to close BitWillet for new signups.
All merchant accounts with active offers will be notified in the coming weeks, and I will be working to help them migrate to other BitCoin payment processors.
If you are a merchant who would like to accept BitCoin, the Merchant Howto and list of shopping cart interfaces on the en.bitcoin.it wiki will be a helpful starting point (although I cannot personally vouch for or recommend any specific service).
At first it seemed like only closed for new signups, which could make sense, but the second part sounds like they will be gone for good. (