If you have a US Airways credit card, log into your account and see if you have this bonus offer on the right hand side of the screen:
When you click on this offer, you will be taken to a page to register to receive 50% bonus miles on purchases from 3/1/15 to 6/30/15. This means that regular purchases will earn 1.5 miles per dollar while US Airways purchase will earn 3 points per dollar. The maximum bonus miles is 10,000 for the period and will be posted 6-8 weeks after the promotion period ends.
Remember that since US Airways and American Airlines are merging sometime in the second quarter of 2015, these miles will become American Airlines miles. This is a nice little miles boost and thanks to Miles4More for posting about this offer.