I agree with Craig, but note that when a domain expires, it's not really ready to be snatched. In fact, a domain only really gets released back into the wild after 75 days past the "official" expiry date and undergoes several stages of death. First, it goes into an "expired" state and stays that way for 40 days. Once that's done, it enters a "redemption" period, and remains that way for 30 more days. After that, it enters a "deletion" stage for a final 5 days. After that, it gets deleted from the ICANN DB and is ready to be purchased again.
Only after this 75 days can one snatch up the domain in question. As Craig eluded to, there are many services out there that watch this countdown clock intently and attempt to grab the domain during the precious few hours after deletion in an attempt to turn around and sell it to someone like you.
There's a good blog post about such an adventure here:
http://www.mikeindustries.com/blog/archive/2005/03/how-to-snatch-an-expiring-domain
I recommend reading it as it will give you a good sense of what to expect. Good luck with the recovery!