Managed to get a hold of the official list to-date of who will be driving where in 2006.
In the following list, blue text indicates confirmed drivers while those in red are still to be confirmed (TBC) or merely have been linked with the drives in question (possible).
Renault
Fernando Alonso
Giancarlo Fisichella
Heikki Kovalainen (test driver)
McLaren
Kimi Raikkonen
Juan Pablo Montoya
Pedro de la Rosa (test driver)
Gary Paffett (test driver)
Ferrari
Michael Schumacher
Felipe Massa
Luca Badoer (test driver)
Marc Gene (test driver)
Toyota
Jarno Trulli
Ralf Schumacher
Ricardo Zonta (test driver)
Williams F1
Mark Webber
Nico Rosberg
Alex Wurz (test driver)
Narain Karthikeyan (possible test driver)
Honda Racing
Jenson Button
Rubens Barrichello
Red Bull
David Coulthard
Christian Klien
Robert Doornbos (test driver)
BMW Sauber
Nick Heidfeld
Jacques Villeneuve
Robert Kubica (test driver)
Midland F1
Christijan Albers
Tiago Monteiro
Scuderia Toro Rosso
Vitantonio Liuzzi
Scott Speed
Neel Jani (test driver)
Super Aguri F1
Takuma Sato (TBC)
Sakon Yamamoto (possible)
Yuji Ide (possible)
Anthony Davidson (possible)
Kosuke Matsuura (possible)