I joined this forum a couple months back because a user left a nice review about our iPhone app, Gaia GPS. I found out when people started hitting my website. Here's that thread: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=29598
So, I thought people might like to know we have released Gaia GPS for Android now, too. It's not as feature rich as the iPhone app yet, but it provides national topo maps, online and off, and we are adding waypoints, tracking, and other features one by one.