Retro Iron Man at it's best.  I have to admit, while I don't like Tony Stark's politics, I love is suit.  Ever since I read Robert Heinlein's Starship Troopers I have wanted one.  I would wear it to the movies and parties, just for laughs.  I was looking for instructions on how to make an Iron Man costume but instead I found this great article on actual, real life exoskeletons.  Very, very cool.  

If, on the other hand, you only want to make a costume, I did find some sites.  This one works, but seems a little low budget.  These instructions seem more like you can make a much more real suit.  Seems you could use the same process those guys used to vacuum form a suit of Stormtrooper armor, but what do I know?