I've often wondered how this process works (one company refers to it as "back-ordering" domains), especially when there are so many places offering the service.
I wonder if your best bet would be to "pre-order" the domain from registrar where it's currently registered? For example, if it's with Verisign then use SnapNames, if it's with GoDaddy then do the "back-order" thing via GoDaddy, etc. It seems that the current registrar would have the inside track to snapping it up if it isn't renewed.
I too waited for a domain name for YEARS, only to see it get taken by a Korean company who put a stupid junk filler page on it. It's very disappointing!
