Least harmful way to disable APN temporarily?
I really like APNdroid and haven't had problems with it at all. However, I've got an HTC Dream that's unlocked and running on AT&amp;T so it is pretty much guaranteed that I'm not getting OTA updates. 

You can always access your APN settings directly, so even if an update broke your APN settings, you should have been able to go in through Settings &gt;  Wireless controls &gt; Mobile networks &gt; Access point names -- I have the option of manually adding one or more APNs and a "reset to defaults" button that will restore the T-Mobile APNs my phone shipped with.