I have a project to make wifi service available to the public visiting a specific area.  Some of the requirements that came out was that the people must be clearly informed of the availability of the service and how to use it.  In my mind this is a communications requirement, but I am stuck as to where to group this.  Technically this is not a functional requirement as it is not a function of the service, neither is it a non functional or even a transitional.  So where do I put it?  Any ideas?

This is not end user documentation yet.  These requirements will be needed to design the soluton properly.  They read something like this:

Clear communication of the availability of wireless access to the internet must be provided to the public visiting the company's grounds

Clear and concise instructions must be provided to the public on how to access the paid internet sites

BABOK V2 defines non-functional requirements as those "that do not directly relate to the behavior or functionality of the solution, but rather describe environmental conditions under which the solution must remain effective or qualities that the systems must have." One of the environmental conditions for the solution to work is that people are aware that the solution exists so they can use it.

Alternatively, you could look at this is a functional requirement that the solution must be able to inform users of the wi-fi - if you take this approach you are broadening your view of the solution from just the IT component to all the aspects invovled in meeting the business need of the organization or its clients (advertising, communications, people, processes, etc.).