There used to be a program a while back that converted jad/jar to ALX, but I can't seem to find it at the moment, or it might have been since removed.
As for your last question: not quite sure what exactly you are asking but OS updates for the phone are usually not done OTA. You download the upgrade onto your computer and it will install to your phone. To see the latest (OS4.5), check out the BlackBerry Curve section of this forum. http://www.blackberryforums.com/gene...ilanguage.html