If you were at last year's Gnomedex, you may remember what a difficult time everyone was having getting connected to the net via Wi-Fi. Apparently, when Chris and Ponzi told the conference center that there would be lots of people connecting to the net, they'd never hosted a Gnomedex before!
If you have EV-DO connectivity, Chris is recommending that you use it at the conference in order to reduce the congestion on the conference center network and Wi-Fi base stations.
That's what I'm using right now at my hotel: my Treo 700p connected to my MacBook via Bluetooth. (I saved the company $30, too since there's a $10 daily fee for a net connection here.) It's pretty cool, except that you have to make sure you have a process running that will keep the connection alive, otherwise you have to reconnect every few minutes. I've found that keeping my blog open in a a browser works as the flickr flash widget continually polls my flickr account for photos.
With all that said, if I remember correctly the Bell Harbor Conference Center was a virtual dead zone for cell phone connectivity, so I have no idea if this will work inside the main room. Plus, how many connections can an EV-DO tower handle at one time? It could end up being slower than the Wi-Fi connectivity. We'll see...