I have released on android market, yesterday evening, "expiry reminder demo".
This app will allow you to track susbcription and warranty expiry, inserting entries in your phone's calendar.
This demo version is limited to 2 events (subscription, warranty or other) and is still in beta version, as I was able to test it only with 2.2 : the calendar app isn't available in android test emulator ...
I will wait a bit before releasing the full (and paid :p ) version.
Meanwhile, I won't start to build an other app. I will concentrate now on improving my other apps already available.