I reckon this story by Paddy Hennessy in yesterday's Sunday Tel predicting a handover by "next summer" is about right, though my money would still be on May 2007 - technically next spring if we're being pedantic.
Hennessy also reckons Blair will sack Hilary Armstrong and try to bring back Stephen Byers in the reshuffle, both of which were also predicted in my Column published the previous day and Podcast available from today.
Other reshuffle tips I've heard: Hilary Benn to go to the Home Office and Charles Clarke to Leader of the House; David Miliband Education Secretary with Ruth Kelly moving to International Development, and Prescott man Dick Caborn to become Chief Whip - possibly as a pay-off for the DPM's rescue act on school reform.
There's also speculation about Margaret Beckett but she will not leave the Cabinet unless it's of her own volition. Blair rates her extremely highly as one of his safest pairs of hands and she is also extremely close to Brown. I could be wrong, but my suspicion is that she would want to stay around for the handover.