A busy weekend coming up. U.S. TV coverage is shown (all times Eastern).

Formula 1:
The San Marino Grand Prix is underway at Imola, with Fernando Alonso (shown above at Imola) topping the time charts after Friday's very dusty practice sessions. Paddock talk at Imola suggests that the coveted 12th (and final) F1 franchise has been awarded to Prodrive. Recall that Prodrive boss David Richards ran the B.A.R.-Honda team until recently. [Photo: Renault F1 Team]

Sunday, CBS 1pm ET

More motorsports after the jump...
NASCAR:
The Nextel Cup teams head out west to the flat, one-mile oval in Phoenix for the Subway Fresh 500, which runs under the lights Saturday night. Last year's winner, Kyle Busch, grabbed the pole, ahead of Greg Biffle and Tony Stewart.

Saturday, FOX 8pm ET

Rolex Sports Car Series:
The Grand American series is at Virginia International Raceway this weekend for the VIR 400. Last year's winners Luis Diaz and Scott Pruett (Lexus Riley) are hoping to extend their championship lead with a good result this year. This weekend will see the debut of the Rolex Series' 30-minute qualifying races, which award championship points. With extra points available, the championship standings could change dramatically after this weekend.

Sunday, SPEED Channel 1pm ET

World Superbike:
The Superbikes race in Valencia, Spain this weekend, and current world champion Troy Corser has put his Suzuki on Friday's provisional pole, only .043 seconds ahead of Ducati rider Troy Bayliss.

Sunday, SPEED Channel 11am ET

AMA Superbike:
U.S. motorcycle road racing returns for the first time since Daytona with the AMA Superbike Championship doubleheader at Barber Motorsports Park in Alabama. Suzuki rider Mat Mladin will be looking to build on his Daytona victory and extend his championship lead at the circuit where he swept last year's doubleheader event.

Sunday, SPEED Channel 4pm ET

IRL:
The IndyCar series is in Japan this week for the Indy Japan 300 at Twin Ring Motegi. The weekend is not off to an auspicious start, with qualifying rained out. Helio Castroneves will start on the pole by virtue of his point standings. Jeff Simmons will be driving for Rahal/Letterman Racing, replacing Paul Dana, who was killed in practice for the Homestead race. The Czech Republic's Tomas Enge is filling in for Eddie Cheever, who is racing in the Rolex Series race this weekend.

Saturday, ESPN 12pm ET