Vibrations in steering wheel

On my 2003 T1.8 Jetta Wagon, I experience vibrations in the steering wheel at highway speeds; the funny thing is that the vibrations cease when I ease off the gas pedal. The tires are brand new winter Pirelli's, and the wheels were just aligned.
I suspect the front drive wheel universal joints could be the culprit...

Any comments would be appreciated.

i suspect the tires because they are winter tread tires. they are horrible for vibrations and noise but excellent when it comes to snow condition driving. I put on a brand new set of bf goodrich winter ta tires on my car and it hums like crazy. You can check your joints by pulling on them back and forth fast and there should be no play.