I just noticed that some of my e-rewards accounts let me redeem for e-miles. This is a very interesting option since e-miles could be redeemed for the following FF programs:
Delta Air Lines®, Continental Airlines®, US Airways®, AirTran Airways®, Alaska Airlines®, Frontier Airlines® or Hilton HHonors®

This could be very helpful to some since not all of the e-miles programs are available for every e-rewards account to redeem for directly.