I presume that the folders 'jre1.60_...' are previous versions. Can I delete these? It seems so but I'd like to be sure ;)
I wouldn't recommend deleting any program files/folders directly, but if you want to clean them up use Add/Remove Programs (or Programs and Features if vista/7 ) and uninstall the java updates(except for the latest of course). I've done this before and it will remove those folders and leave the latest installation of java intact.