Well, drivers so far seem to be:
McLaren-Mercedes
Jenson Button and Lewis Hamilton
Mercedes GP (Yes used to be called Brawn GP)
Nico Rosberg
Seat 2 - Nick Heidfeld? Michael Schumacher?

ooer
Red Bull
Sebastian Vettel and Mark Webber
Sounds pretty sensible
Ferrari
Fernando Alonso and Felipe Massa
Hooray Massa is back (and winning kart races already)
Williams-Cosworth
Rubens Barrichello and Nico Hulkenberg (was the test driver)
Renault (if they are still there mind you)
Robert Kubica
Seat 2 - Kovalainen? or Grosjean again?
Force India-Mercedes
Adrian Sutil and Tonio Liuzzi
Go Sutil!!
Toro Rosso-Ferrari
Sebastien Buemi
seat 2 probably Jamie Alguersuari
US F1
No drivers confirmed
Jose Maria Lopez maybe if he brings a wad of cash
Campos Meta
Bruno Senna
Seat 2 Pedro de la Rosa? Nelson Piquet?? (will bring some cash to the team no doubt)
Virgin (Manor team)
Timo Glock
Seat 2 tipped for Lucas di Grassi.
Lotus
No drivers confirmed
Jarno Trulli??
Sauber - Yup Peter Suaber bought his old team back from BMW and the FIA kindly allowed him to have Toyota's slot.
No drivers confirmed
Ex-BMW test driver Christian Klien might get a drive.
Unsigned 2009 drivers: Jarno Trulli, Heikki Kovalainen, Giancarlo Fisichella, Kazuki Nakajima, Nelson Piquet, Romain Grosjean, Kamui Kobayashi
Old hopefuls: Jacques Villeneuve, Pedro de la Rosa, Christian Klien, Alex Wurz, Anthony Davidson, Takuma Sato, Franck Montagny, Michael Schumacher
Others: Lucas di Grassi, Vitaly Petrov, Pastor Maldonado, Andy Soucek, Karun Chandhok, Bertrand Baguette, Paul di Resta, Jose Maria Lopez