The Old Saco River is loaded with fish! Summer of 2012, guests were catching bass every 20 minutes or so! Bring your rod and gear and have a go for yourself.
The Maine Fishing Guide gives you details of other rivers and lakes in the area, and any permit information that you'll need. Their guide uses GoogleEarth and is very useful. The NH Summer Guide has a great article detailing numerous fishing spots. See the article here. If you'd like guide services, Rocky Ridge offers fishing and hunting services in the area. Ever tried ice fishing?