This seems like a pretty decent way to support the troops and get rid of some of those old paperbacks at the same time. To quote their website:

"Books For Soldiers started in 1991 during the Gulf War I. We heard from many of our family members and friends about the long waits with hours and hours of nothing to do. We sometimes forget that our service people are alone, thousands of miles away, with nothing to stimulate them intellectually.

"During the first Gulf War, we collected almost 1000 used paperback books and sent them to our friends serving in the Gulf and they passed them out to their fellow soldiers.

"We received many notes of thanks, after the war, from soldiers who got one of our books, read it and passed it on. It made the time away from family pass more quickly."

Click here if this sounds like something you'd be interested in.