Intel has a pretty cool idea for a virtual assistant for mobile users that they call Persona. Their research paper uses a travel example to contend that reformatting data and user interfaces for mobile/PDA access still makes it difficult for the user to deal with.
Instead they suggest the concept of a virtual assistant that can assess the complex information and reduce it to a few simple choices on the part of the user. For example, rather that forcing the user to check schedules on their PDA, change car rentals and hotels, and inform colleagues, Persona can instead prompt the user with just a few flight options, dealing with everything else in the background.
In fact, as site like Expedia or Travelocity has the capability to do a lot of this already, and would merely need to be exposed as a service for mobile network operators, perhaps through the Open Service Access (OSA)/Parlay specification. Imagine reducing your travel headaches to a simple one screen selection on your mobile handset.