Might as well start up this topic since it will happen when John Kerry is appointed Secretary of State.
The election will be sometime in June assuming he is appointed in January after the 180 days "campaign".
Rumor has it that Barney Frank will be the interim senator until the election.
The first Democrat to step up to the plate is Ed Mackey and he is not very well liked in the state [Harry Reid lite]. A lot of MA residents want a younger person to run because Warren is already in her 60s and may get 2 terms out of the ordeal. Course Brown will likely be the GOP nominee.