Now that USF1 has been officially accepted to the 2010 entry list, who the heck are they going to have drive their current vapor-ware cars?
"Drivers previously mentioned include second generation racers Graham Rahal, Conor Daly and Marco Andretti as well as NASCAR's Kyle Busch, former F1 racer Scott Speed and AJ Allmendinger."

Although Speed lost his seat to Vettel, one of the current best drivers in F1, Speed might be the best choice for the short term, as he's 'been-there-done-that'.
Everyone else would be too busy trying to find their A$$ with both hands to keep the car pointed in the right direction.
Busch wont go, he's got too much to lose.
I just don't see anyone from the US strong enough at the moment to step into F1 and be successful.

The other newbies

I doubt Kyle would go over.  But Speed has alrady expressed interest in getting back into F1.  So I could see him and maybe Marco.

They have also turned down a coupl of un-named GP2 drivers with wheel-barrows of sponsorship.

"We've been offered well over three-quarters of our racing budget by two drivers already, neither of whom have raced in Formula One but have both won races in GP2," co-principal Peter Windsor told Sports Illustrated, adding that neither driver was American."

However:

US F1's aim is to give both cockpits to young American hopefuls. In 2010, however, one of the seats could go to an experienced non-American veteran, for instance Austrian Alex Wurz.