When I used to volunteer for Black Hat, we had one guy from Aruba and he helped set up the wireless access points around the conference, the same access points are also used at DefCon [1]. They are able to provide a lot of insight into the radio signals, where people are, where the most activity is, where there are blind spots and all that fun stuff.

Their gear is small, lightweight and from what I have heard from other people using it, absolutely fantastic to manage.

[1]: http://www.wired.com/threatlevel/2008/08/a-first-ever-lo/