You may have encountered this puzzle previously -- it is a great challenge -- a good way to test your web development skills and a nice diversion from coding sessions. The most important outcome is not finding the hidden message -- I will eventually reveal what it is if there is enough interest and people keep working toward a solution -- but explaining how you arrived at it . This exercise also illustrates the futility of trying to hide source code.
I've solved it, the simplest way I think
Good test, actually, to check one's ability to solve the problem the most effective way.
Congratultions zerg! Why don't you post the hidden message here and I will tell you if it is correct? But don't post the way you solved it just yet (a little later please) in order to let others have a shot at solving it their way.
I also found it using the same method as above (in IE9), but because I was interested to know how it worked I went through all the methods of obfuscation and deception used in order to hide the end result. I can be more detailed if requested by the OP.