MSNBC had the scoop this morning:

NBC News has learned that Trent Lott's in the midst of informing close allies that he plans to resign his senate seat before the end of the year. It's possible a formal announcement of his plans could take place as early as today.

Josh Kraushaar has more, including speculation about potential candidates for Lott's Mississippi seat.

UPDATED: (Nicole) PERRspectives looks at some possible new careers for Lott.