After installing the really awesome CyanogenMod on my G1/HTC Dream I was facing the problem that the keyboard layout was switched to qwerty - while I really prefer that on all my computers, it is annoying to use if you have to guess all the Alt keys.
There are several opinions out there about what to do to change the keyboard layout - the following procedure works well for me:
First download the android sdk if you haven't done so yet, you'll need adb from the tools directory. Connect your phone via USB and run
to check if adb is able to detect the phone. If not, you probably need to setup the device permissions correctly. If adb is able to detect your devices, use it to remount /system read-write and enter a shell:
adb remount adb shell
Paste the following into the adb shell - please note that the phone will reboot. If you don't want that, don't paste the reboot line.
cp /system/usr/keychars/trout-keypad-qwertz.kcm.bin /system/usr/keychars/trout-keypad-v3.kcm.bin cp /system/usr/keychars/trout-keypad-qwertz.kcm.bin /system/usr/keychars/trout-keypad-v2.kcm.bin cp /system/usr/keychars/trout-keypad-qwertz.kcm.bin /system/usr/keychars/trout-keypad.kcm.bin cp /system/usr/keylayout/trout-keypad-qwertz.kl /system/usr/keylayout/trout-keypad-v3.kl cp /system/usr/keylayout/trout-keypad-qwertz.kl /system/usr/keylayout/trout-keypad-v2.kl cp /system/usr/keylayout/trout-keypad-qwertz.kl /system/usr/keylayout/trout-keypad.kl reboot
Now your keyboard layout should be qwertz again.