yes there is... its been here forever:
After you install and patch the game (you are done patching if you can see the login screen)
exit the game and locate the folder "L10N" -- C:\Program Files\Ê¢´óÍøÂç\ÓÀºãÖ®Ëþ\AION\L10N
place the english patch in this folder and then launch the game -- it should now be in english
EDIT: TESTED AND WORKING - playing now