There are quite a few news outlets that are reporting Trent Lott will resign his seat today. Politico and Think Progress are two that have stated it so far via emails I rec'd from both of them. From the ThinkProgress writeup:
Sen. Trent Lott (R-MS) is reportedly informing close allies that he plans to resign his Senate seat before the end of the year. NBC reports, "It's possible a formal announcement of his plans could take place as early as today." Politico adds, "If he resigns, Lott would become the sixth Republican senator to announce they were stepping down this election cycle."
Lott's term expires in 2012, therefore a resignation would trigger a special election for a replacement to serve the remainder of his term.
UPDATE IV: "While the exact reason Lott is stepping down before he finishes his term is unknown, the general speculation is that a quick departure immunizes Lott against tougher restrictions in a new lobbying law that takes effect at the end of the year. That law would require Senators to wait two-years before entering the lucrative world of lobbying Congress."
Its all about the money isn't it? Getting a high-paying job for one of the huge corporations he has already worked for..you know..instead of the people that voted for him? Greed..what a concept!