If you simply must get all mobile people to your mobile site, you'll need to do detection on the server using a tool like Wireless Universal Resource File (WURFL) (http://wurfl.sourceforge.net/). It is the ultimate community-maintained database of wireless device descriptors. It's basically user-agent sniffing, but with an up-to-date, well maintained, community database. WURFL can tell you all kinds of useful things about each device that visits you.
The link http://www.scientiamobile.com/wurflCapability/ will give you a complete listing of WURFL's capabilities. We'll get into the nuts and bolts of this in Chapter 9.