From the Politico.
Sen. Mel Martinez (R-Fla.) will be resigning from the Senate, according to several senior Republican sources familiar with his thinking.
He made the announcement at a morning staff meeting, where he said he will not be returning to the Senate after the August recess.
I'm guessing that Crist will be the one to nominate the replacement. I have no idea at this time if Crist can nominate himself to the Senate early or if he has to put in a place holder. This does have the makings of some behind the scenes deal that went down late one night.