No - but loads of rumours flying around.
Firstly, it's been confirmed that Big Brother's Big Brain has been axed. No surprise really as this was a sweetner for Dermot with BBLB moving to E4, but with Dermot likely to leave after BB8 when he takes over on The X Factor, C4 have no reason to keep him happy. Presumably Mondays BBLB will therefore return.
And the rumour mill, mainly courtesy of BBUKsite.net and BBSpy.co.uk

Big Brother 8 will launch on Thursday 24th May.
doesn't take a genious - Peep Show etc. are scheduled to end on Fri 18th May, so BB beginning the week after is pretty obvious

It will last for twelve weeks and one day and will finish on Friday, 17th August.
speculation - Kevin Lygo said it wouldn't be more than last years 93 days - though he didn't say it would be shorter as often misreported in the press. I'm holding out for the full 13 weeks myself.

Big Brother will not be going back to basics.
probably true

The 'Red button' live feed will be available on Sky, cable and Freeview.
cable and sky almost certain - more hope than expectation with Freeview - I think they'll keep Film4+1 myself

There will be either 13 or 14 housemates entering on launch night. It is still undecided.
well, that's pretty obvious

The main rumour doing the rounds is that the show will be branded Big Brother: The Battle, and develop the idea of the divide from BB3 to the extent most European countries did at the time, with one rich house and one poor house. Producers have already gone on record claiming this series will be "very different".
Although perhaps they should have done it sooner, I wouldn't mind seeing the Rich-Poor idea explored further as I think we only touched the surface of it in BB3. I personally liked the twist alot, but alot of people claim they didn't. However, BB3 is still by far the highest rated series, averaging close to 6m viewers compared with around 4.5m for other series.

Finally, the newest rumour is that the jackpot will increase by ten-fold to £1m - making it the biggest Big Brother jackpot in the world.