On a more serious note...I would have thought it made a difference what part of the country you are in, different climates dictate the seasons that Fish breed with the warmer parts of the Country inducing Spawning quicker than the colder parts.
In all seriousness he's right about the climate/environment stuff too. Wikipedia says they spawn in june, but it might be later here in canada. I've heard of really cold springs delaying some species like bass from spawning.
When I was on the toronto islands recently I saw a small school of sunfish, no more than 1" long. I doubt theyre a year old, so they've probably already spawned. I wouldn't be surprised if they spawned all summer.
I keep my boat on Sturgeon Lake near Lindsay Ontario, and the bluegills have been in spawing since ice-out. Just like crappies, look for shallow, warm bays and inlets (1-4' of water) with good structure and cover. Theyre still in there and will probably move out soon as the water warms and the oxygen levels drop.