There was recently a Poweraid commercial that included Andy Roddick
serving the ball and getting it stuck in the clay, Is this actual
footage of the French open or is it good computer graphics of the ball
getting stuck in the clay

it was featured on a computer show.  it is very good computer graphics.

See

https://answers.google.com/answers/main?cmd=threadview&id=29930

and

https://answers.google.com/answers/main?cmd=threadview&id=29927

-THV

I haven't seen the commercial, but I'd say it's probably the real
thing. I actually saw a match where Roddick served the ball so hard it
partially buried itself in the clay. It didn't bounce up at all, and I
remember seeing close-ups of the ball stuck in the clay. 
Unfortunately, my feeble brain doesn't recall whether it was at the
French Open or some other tournament, or even who the match was
against.  I tried to find some confirmation online, but the only
reference I could find was at TennisWizard.com,
http://www.tenniswizard.com/dynamic/home/ask/index.cfm?ID=2381&sec=lib&cat=Events,
which reported that Roddick served the ball into the court in
Dusseldorf, Germany, during World Cup match play against Alex
Corretja.  Hope this helps.