Ball joint removal/re-install kit.
You can rent one at the local parts stores. I rented one at O'Reilly's. Actually, I think I had to PAY for it up front ..... and got every penny back when returned. Be prepared if you got this route .... they're kinda expensive.
EDIT: you also need a BFH to go along with the fork. If you get the tool, you may not even need to use a fork. It's a PITA to do ball joints. If possible, get the control arms that already have them installed in them.