"Getting root on your phone involves exploiting a security hole
that existed in an early version of Android. The versions with the
security holes are known as RC19, RC28, and RC29 (or RC7 or lower
for UK phones). As of RC30 (RC8 on UK), Google patched the security
hole so that your phone can not be rooted (don’t worry, we
can still root it!).
"To check your version, go to the Home Screen, click your menu
button, choose "Settings", and then click "About phone". You will
then see the following screen:
