Heat on the out side of the system is not a bad thing in the slightest though, as long as they're not in some enclosed area you really want them to be hot outside and not inside, I wouldn't worry too much about it though, pretty much any computer electronic now will shut down long before it gets to a point where it will suffer damage from heat, the only times there is exceptions to this shut down are by manufacturing mistakes or just oversights in the OS.
-Red Ring of Death caused by poor solder
-Wii GPU damage caused by the system generating a lot of heat in standby mode by connecting to the internet without fans powering up.
Like I said, unless it starts to shut down on you don't worry about it, just make sure you got a nice ventilated area at the back of the consoles and of course make sure it isn't resting on carpet! That'll murder a console.
Why not check me out on youtube and help me on the way to 2k subs over at www.youtube.com/stormcloudlive
