Ok guys, im new to the forums, and new to Android, but i've got a 2.1 Desire, rooted, and i've got the SDK (and ADB) installed on my PC.
My goal was to remove CityID for good, not just until the phone was rebooted, and finally got this to work. The end result was that i was able to remove not only CityID, but Twitter and all the other stuff i'll never use. Gone from Apps Drawer, gone from Uninstall screen, gone after reboot :-D
This involves ADB IN RECOVERY MODE, which many posts made out to be extremely difficult to get the timing right, special SD cards, a bunch of voodoo and magic, blah blah... I got recovery mode on my phone simply by typing
ADB REBOOT RECOVERY
then i had to mount /system (using Clockwork Mod on the phone, tho suppose it could be done via ADB), and was able to simply "rm CityID.apk", and even after rebooting the phone, it's still gone, no trace of it.
Whole process took about 2 min, and was very easy... no "rapidly inserting and removing the memory card", no cooking live animals in a vat of boiling water while chanting in latin, or any other nonsense.
Furthermore getting the phone into ADB recovery has worked flawless each time i've tried it. If this is something new, please respond and i'll be happy to write up a more detailed description.