I just wanted to chime in with another vote for Momentum (
http://momentumplanet.ca/). This is a magazine published in Canada that comes out once every two months. Earlier this year they began entering the US market and you can get a very reasonable subscription to them. They cover a lot of aspects of bicycle commuting as well as general bicycle culture. It's very well written and has a wide variety of topics, from legal issues to case studies of folks and communities working to increase the use of bicycles as transportation.