Hi There,
A while ago I worked a project for a Govt ministry that required something similar. I was the one of the architects for that system. The application was divided into four broad categories: Where, What, How and When. Where is the information located? What format is the information available? How to get it? When to get it? These broad description answered themselves as we went looking for information pertaining to policies, procedures, complaints, prosecutions, assistance etc. If youare looking at a more non-specific items like locations in a city (restaurants, clubs etc.) there is lots of manual work to be done to create a repository (either a database or a Lotus Notes type of environment which allows updates). The released information will be available online when it is PUBLISHED.