There are several sites with alternative currencies that can be exchanged to Miles or Points - check out the following:
http://www.mypoints.com/
http://www.airmilesmart.com/
http://www.goldpoints.com/
http://www.clickrewards.com/
http://www.milesource.com/
http://www.milesmall.com/
http://www.skymall.com/
http://www.greenpoints.com/

FWIW, I got these links off the S.P.A.M. forum . . . there's a ton of ideas in there to maximize your points and rewards for traveling. Hope that helps!