If ever there was a testament to the potential of exoskeleton technology, it is the vast amount of interest being shown by both independent and federal researchers. Projects aimed at developing powered exoskeletal suits are being pioneered at several major universities as well as by commercial groups and even departments of the United States government.
The history of exoskeleton technology in reality goes all the way back to the 1960s with General Electric's suit "Hardiman" which was never successful. The concept of a powered exoskeleton which enhances the wearer's strength in fiction, however, has been around since at least the 1930s when E.E. Smith published his Lensman series (Wikipedia).
Since the days of Hardiman, technology has advanced significantly and it is not possible for several fully functioning suits to exist. Linked on the left hand side of this page is a description of a few of the suits which are functional or close to it.