Phelps will only be 27 for London so I say compete and make the record untouchable. He will be a more experienced faster swimmer and break at least half of his own records. After that retire with the multi-millions and the legendary status.
If he walked into a room of GetBiggers, could you identify Michael Phelps without someone saying, "Hey, there's Michael Phelps"?
He and his coach have already begun planning for London 2012.
Between now and then, however, most of the world will be more focused on real sports.