Actually, there's a simpler way -- Randy's Mileage Converter.

http://www.webflyer.com/programs/mileage_converter/

Unfortunately, according to the tool, you need at least 160K US Dividend Miles in order to convert them to MR points, and if you had 160K miles, I don't think you'd have much of a problem finding somewhere to go with them.

Regrettably, even if you've got 160K US miles, the 'exchange friction' results in confiscatory devaluation of your miles:

US Airways Dividend Miles converts to (starting) 160,000
Hawaiian Airlines HawaiianMiles (at a ratio of 4:1) converts to 40,000
Hilton HHonors (at a ratio of 1:2) converts to 80,000
American AAdvantage (at a ratio of 10000:1500) converts to 12,000
Diners Club Club Rewards (at a ratio of 1:1) converts to 10,000
Marriott Rewards (at a ratio of 2.5:1.5) Total: 6,000

Holy cow! No thanks!

edited to add: I recently emptied out my AA account by exchanging my last few hundred miles for magazine subscriptions. Perhaps US has a similar offer? At least you'd get something for the miles that way.