I think each team gets 3 days of testing for new drivers. I bet Williams would rather give the Hulk more time in the car than having to test Andy Soucek. I've had a scout round quickly, and here's a (probably imcomplete) list of which youngsters are testing for which teams -
Red Bull - Daniel Ricciardo (Aussie, British F3 champ)
Ferrari - Daniel Zampieri, Marco Zipoli and Pablo Sanchez-Lopez top 3 Italian F3 drivers respectively. The last Italian F3 driver to graduate to F1 was Giancarlo Fisichella in 1994...
Williams - Andy Soucek (F2 champ) and Hulkenburg
Toro Rosso - Mirko Bortolotti ('08 Italian F3 champ, has tested Ferrari's before and holds the unofficial lap record around Fiorano), and Brendan Hartley (RBR tester, former member of Hanson)
BMW Sauber (yes, you did read that correctly) - Alexander Rossi + Esteban Gutierrez - 2 highly rated drivers, pity they're testing for a seemingly defunct team
McLaren - Paul Di Resta (good driver who is gonna get stuck in DTM if he isn't careful)
Renault - Bertrand Baguette (Belgian, Formula Renault 3.5 champ. Never heard of him

), i have also heard a rumor that Di Grassi will test for them.
Force India - Karun Chandhok (kinda predictable)
n.b. Kobayashi is apparently eligible to test here, i have read his name and Lotus mentioned in the same sentence several times....