I haven't noticed it except for when I am charging which is normal. It might also depend on what your doing. I know mine will get a little hot if I'm using GPS.
But seriously, it's more than normal; it's expected. The energy stored in the battery is converted into light energy (screen/camera flash) and heat energy.
You said porn once, you didn't have to say it twice! LOL
But yes, it's normal for it to get a bit warm now and then. If it gets too hot, there's a warning system, so you'll know if there's a problem and the temp is going too high.