You should be able to pop the top off. Once the top is of there is a nut that unscrews and and you can up it out the front. here are wrenches for this, (http://www.buy.com/prod/heavy-duty-beer-faucet-hex-nut-wrench/212996840.html?listingId=61767042), but as long as you can get a wrench down in the front that fits, you'll be fine.
Sorry, I mean pop the top off the tower. Should just pull strait up and off.
Another link http://stores.kegconnection.com/Detail.bok?no=167