Paul, first, the next version of LEED to come out will be LEED 2012. We don't yet know when exactly it will come out, but as you can guess from the name, you have a little while yet before it's in effect. So I would not be in a rush to register a project. However, there is no deadline to certify a project once it's registered.
When LEED 2009 came out, projects were given about 6 months to upgrade from past versions of LEED without paying a new registration fee. Now that period is passed, projects do have to pay a new registration fee. I am guessing that LEED 2012 will have a similar set-up, but we won't know for sure for a little while.