I noted the new numbers in a recent blog post of how many MP3 devices are "in service" in the U.S., but I have two other more obscure indicators of the growing "mainstreamness" (is that a word?) of portable media devices …

1. Joseph Guinto has a piece on "IPOD PLAYLISTS" in Southwest Airlines Spirit in-flight magazine published for Feb05.
2. California’s AAA Westways magazine had a detailed section on iPod and other MP3 player devices plus accessories for your car.

Note: In digging into who does the Spirit magazine, it turns out American Airlines via AA Publishing does the magazine for Southwest.  You can find out more about Joseph Guinto via Google (he seems to write a lot).