Is there a way to update to Amarok 2.4.3 in Ubuntu 10.04 LTS through Software Sources yet (PPA), or are there any plans on making this update available for Ubuntu 10.04 LTS? Thanks!!!

The Kubuntu backports PPA usually only provides updates for the previous Ubuntu version. 2.4.0 is available in main Ubuntu backports, but no more recent versions. I'm not aware of any other repositories with more recent versions.
You can't really expect up-to-date software on an LTS version of Ubuntu; that's not what it's designed to do. Update Ubuntu or build it yourself (this may not be a simple matter, as Lucid may not have sufficiently up-to-date dependencies).