That is Zarqawi's nom de guerre - he is known as Abu Mus'ab or Abu Mus'ab al Zarqawi. But his real name is Ahmad Fadil Al-Khalailah.
I have done a search on that board and he is the ONLY Abu Mus'ab registered.
Or you can go to Google and search for "Abu Mus'ab". The only returns you will get will be for his namesake, an early martyr from the early days of Islamic history, and Mr. Zarqawi.
However, you are of course free to draw your own conclusions, as am I :)