I don't like lugging laptops to conference so I thought that I would try to rely on my Blackberry, iPod Touch, and Sony Reader. I made a big mistake on the last device; I forgot the power cord for my Reader. There I was foolishly reading my book while listening to music on my Reader (so that I could conserve power on my other devices). Of course this drains the battery like nobody's business. I also brought a digital camera, not thinking about how I would upload those pictures. Luckily the hotel had a business center and I was able to upload pics just fine.
I tried Foursquare with my Twitter account. I felt Foursquare was valuable for the conference, but doubt that I will use it outside of that. Foursquare is a good tool if you already know people and are in close proximity, fostering social connections, especially at a professional conference in a new city. It was a great tool to see who was around and I got to meet people in real life that I only knew on Twitter. I geeked out a bit and put my Twitter handle and picture on my badge as well. It was helpful and fun to associate a photo with the Twitter persona.
Overall, I would say the mobile conferencing was a success.