The onyl way to really know whether magazines are worth it is to use actual magazines you'd buy. I ran the numbers on Business Week, and the rate was about 2.5 cents/mile.

You don't have to be solicted to buy magazines with miles. Here's a listing from Mileageworkshop.com for various airlines. Just call and get a catalog:

Alaska Mileage Plan: 800-861-1470
American Express Mileage Rewards: 800-297-3276
America West FlightFund: 800-961-8505
American AAdvantage: 800-961-8669
British Airways Executive Club: 800-586-9309
Continental OnePass: 800-961-8697
Delta SkyMiles: 800-961-8702
TWA Aviators: 800-961-8721
United Mileage Plus: 800-961-8723
US Airways Dividend Miles: 800-586-9632