What do you mean USB host?
What I meant was that the USB port is constantly drawing power. Plug a charger into your phone, one with an LED on it. Don't plug the charger in to the wall, but notice the LED is on. Do that when you're in Winmo and it doesn't light up. The USB doesn't seem to be able to turn off at this point. There's a thread about it somewhere...
found it
http://forum.ppcgeeks.com/showthread.php?t=131383
Anyways, Astro can be obtained from the Market