I have enabled kde-unstable and kde-unstable-all. This allows me to use kde4.0.83, a terrific improvement over kde4.0.5.

There are bugs, so be forewarned: kde-redhat is presently providing beta releases (kde4.0.5 can at best be considered an alpha). And, yes, there are some conflicts. I found that I had to uninstall kipi-plugins, digikam, libkipi and libkdcraw. I prefer digikam to gwenview and the kipi-plugins are nicer to use than ImageMagick, but I will likely only have to put up with this minor inconvenience until the end of July, when kde4.1 is officially released.

This will get your system upgraded:
sudo yum --enablerepo=kde-unstable --enablerepo=kde-unstable-all update

Once kde has arrived at a more robust and stout level of maturity, I will likely discontinue use of kde-redhat. I cannot predict how rocky the road back to the official fedora repositories will be, but I expect that it will be a very smooth one, as the version numbering and kde-sig should take care of that very competently.