Strobes are fascinating little devices that can light up a huge area and be far less annoying to spectators than on camera flashes.
I Had a long chat with an AP photographer at an NHL game who showed me the strobe remote mounted on on his camera-worth-more-than-my-2-cars-combined. I think it was a Skyport made by a Swiss company.
The strobes are permanently mounted in the ceiling, at least 10-12 stories up and photogs use these remotes to trigger them. They produce really pleasant white light with a minimum of shadows.
It varies from arena to arena. Some have them mounted and offer them to photographers to use for free (publicity is good), others charge a fee, some newspapers install their own in the catwalks and set them up the way they want.
The Salt Lake paper had a nice article about use of these strobes for NBA games
http://166.70.44.68/blogs/trent/2006/11/jazz-up-in-the-ceiling/
You also have to have a number of strobes to get good fill
http://www.daveblackphotography.com/workshop/arena-lighting.htm