Yes you can. You will need to edit the XML files that govern the icons that appear in each category. See this thread: http://www.ps3news.com/forums/ps3-ha...er-113703.html
Open the XML for the Game category and locate the <Query that is for the Install Package Files entry and copy it (be sure to get the closing tag />) to the same location the XML for the category you want to move it to. Be sure to delete it or comment it out from Game. I renamed my PSN category "Applications" and moved my BuM, Payload, Install Package Files, FTP Server, and SNES9X over to it. Leaving Game nice and clean. I also got rid of a number of other icons. Check the thread above for details.