Just got a new Airport Express, and am trying to get it on my network for streaming music via AirTunes. My setup: AEBS (n-model, running on a g-compatible mode). AppleTV (which works well, and does work with AirTunes). MacBook (wireless-g), Powerbook (g), 2 iPhones, and a TiVo with a wireless-g adapter. To this, I'm adding Airport Express. It's going through the set up ok via Airport Utility. I select the APex to connect to my existing (AEBS) network. The APex shows up in iTunes as a speaker destination, but when attempting to select it, iTunes chugs away for a few seconds, then reverts back to the default "computer" setting (or AppleTV setting, as the case may be). Further, after being on for a few minutes, Airport Utility stops seeing the APex. I've tried hard resets, and actually returned the first one I bought, hoping it was a hardware issue. Whatever... the new one does the same thing. Any ideas on what to try?