Shorter version for print
Dispatch is basically a system to collect, process and disseminate accurate, reliable and up-to-date information about protests and events. There are many different ways and techniques to do this but the main principles remain the same. There are three main elements/processes that make up Dispatch: incoming info (reports, phone calls etc.), processing (confirming, double-checking and structuring the data) and outgoing info (timelines, articles etc.).
In addition to the obvious things such as technical and logistic arrangements, preparation means Dispatchers should know enough in advance about the issues/actions/campaigns they will be working on to avoid embarrassing mistakes. Maps and large sheets to stick on the wall are some of the obvious things you would need. Write down a detailed timeline of the action/campaign/event, including all planned actions. Find out times and places of meetings in the convergence centre(s), plenary sessions, info meetings etc. The most important thing is probably contacts: in addition to publicising your dispatch phone numbers, you should have a list of the contact details of the relevant groups and activists as these would be a vital source of information/confirmation. Finally, make yourself familiar with IRC, SiLC and the like in advance, as these are usually used for Indymedia Dispatch.