I often find myself making very high-level sketches of UIs in order to illustrate information architectures. For example, I want to show that a certain page displays a certain kind of information, and links to certain other pages in certain ways. But I'm not really attempting to design anything: I ultimately hand these schematics over to a real designer, who is responsible for figuring out how to actually present the information on each page.
Can anyone recommend any tools for me to use at the "information architecture" level? To be clear, I do want to generate actual UI mockups, but I don't want to make any decisions about the design or layout of this information.