I made a few calls today to see what the local park and rec. department and the local state park felt about geocaching in my area.
The park and rec department informed me they are aware of the presence of geocaches on city grounds, but have no current stance on if it is legal or illegal as such an issue would need to be brought up before the city council and thus far has never reached that point. They also informed me that any cache found by a employee of their department is pretty much at the mercy of that employee as to decide to leave it be or remove it.
The individual working the gate of the local state park told me that he is familiar with geogaching and the caches located in the state park grounds and that he has never recieved an offical order from the state on any need to obtain a permit to hide a cache on the grounds of the park. He also told me that he has met many friendly geocachers in the park and that 80% or more of them tend to pick up litter on their way to and from the caches and he personally finds it a interesting and harmless hobby.
Honestly I use the "frisbee rule" myself when it comes to parks and forests, but did ask permission before hiding the only cache I've yet to put out as it was on private property.