This happened to me also.. It has something to do with the apps going to the "Media area" instead of the SD Card like we are all used to. A software issue that will hopefully get fixed.
To fix it on your phone, follow the instructions that Sweeeet posted above. Menu....manage apps.... media area.... move to phone.
If the apps are not showing up in the Media Area, reboot your phone. I had to move a few, reboot, move a few more and continue the process until all the apps in this section no longer have a green check mark next to them. It took me about 5 reboots but in the end I was able to move them all back.
If this doesn't work, redownload the apps and don't move them over. Hopefully a fix will come out soon.