Mobile users will be looking for a way to move your information into the tools they are using. This means that (today) things like events should be available as vCal objects and contact information as vCard. In the near future there will probably be demand for encoding microformats or RDFa into HTML also. This will allow users to say “hey, I want to attend this” and add it to the tools that they actually use, for example, their calendar or TripIt or similar.

In-destination, the emphasis of a mobile site should not be marketing: the user is sold, they’re there. Instead, it should be rapidly allow users to navigate to information they’re interested in consuming in the most convenient possible way. This means 1) allow users to quickly see navigation items 2) present location information based on proximity (if GPS is available) and 3) event information based on date. IMHO concepts such as “the entertainment district” may have to become deemphasized as this is an organizational unit more suitable to printed pages that mobile devices.

As you say, respond quickly to inquiries. In a user is using a mobile device in-destination, they are likely to be very deep in the sales funnel and conversion should be made as simple and painless as possible.

Page load speed is as critical as possible. This is true in the web browser world too, but in mobile: 1) minimize JavaScript, as there’s probably not a lot of value or CPU cycles to do it 2) minimize page size, as that corresponds to time-to-download and also cost to the user. Since the traveler is likely not to be using their normal carrier, they’ll appreciate the effort.

Consider automatically redirecting the user to your mobile site (e.g. m.example.com) if they’re hitting your “normal” site (e.g. http://www.example.com) from a mobile device, or at least prominently showing the user the option to do this. If you have an iPhone or BB app (this is more a DMO level task), make sure that links to that are available also.