The Android Emulator provide a powerful way to test Android applications. But it not allow you to test root apps because
So if you want to test root apps you have to get a rooted emulator. It's mean a su binary and optionally the superuser app which allow you to manage root apps.
adb shell mount -o rw,remount -t yaffs2 /dev/block/mtdblock03 /system adb push su /system/xbin/su adb shell chmod 06755 /system adb shell chmod 06755 /system/xbin/su
adb install superuser.apk
[Update April 2012] : This tip doesn't work anymore, see comments for more information