I've been developing in Android for just over a month, to date I have written 2 applications and 2 widgets, the applications:
"Racing Start Lights" and "Drag Lights", both intended for use wth slot car racing sets, I will add comunications later to these applications to allow them to transmit a packet to race software to signal start, for now they just simulate race lights.
"Wallpaper Rotator" and "Wallpaper Rotator from SD Card", these are both widgets, the first one is a free download but requires a registered account on http://avasig.com where the images are hosted. The second widget is 1.5 GBP and gets the images straight from a folder on your SD card. The only known issue with these widgets is that following a reboot the widget must be kicked on again, I will be addressing this issue in the next day or so.