T-Mobile G1 users will be getting an OTA (over-the-air) upgrade to the Android 1.5 "Cupcake" which is being pushed by T-Mobile randomly this month. Some of the features that are coming with the upgrade should have been there on the initial release and have been far pass due.
A new radio has been added on this release which should help the battery life as well. A few things that were not mentioned on the release also include contacts photo appearing next to the contacts name, home screen widgets, voice search, and of course a call log that makes sense. The Android 1.0 told you how long ago the last call was made but not what time. The Android 1.5 displays what time the last call was made (this feature should have been available on the 1.0 release).
Would you like a Cupcake?