The Visio stencils (by Nick Finck) on his page are free for downloading and using.
They are designed to aid the work of Information Architects.
Download: All three stencils (122 KB .zip)
Wireframes (sometimes referred to as schematics, page architecture, or blueprints).
A Sitemap (in the since of a IA Deliverable) is a digram or flow chart that maps out the architecture or structure of a web site, web application, or system. These are typically constructed of boxes which represent pages and lines which connect the boxes that represent which pages can be accessed (hierarchically) .
Process Flows (sometimes referred to as User Flows, Visual Vocabulary, Task Analysis, or Process Maps).
EROL MVP SPS