The guided fishing tours start out at $200+ for a 2 hour cruise. It is strictly catch and release, but if you hit a good day you're going to catch a lot, and have fun. The guides are all BASS certified and they will provide you with drinks.
As far as fishing on your own is concerned...I think you used to be able to rent poles and fish over by PO, but I'm not sure if that is allowed any more.
The guided fishing excursions can be had on Bay Lake/Seven Seas (pick up from CR marina I think), and World Showcase Lagoon/Crescent Lake (pick up from YC marina).
Its a very nice experience, and I highly recommend it.