IT Pros often have to produce maps of “as is” and “intended” architectures for reporting and funds-getting purposes. For example, if you are pitching for funds for SharePoint 2010 farms – you might find this Services in SharePoint 2010 Poster handy. If you are interested in virtualization, check out the deepzoom online version of the Windows Server 2008 R2 Feature Components Poster for IT Pros.
NOTE: You can make your own deepzoom online versions of architecture diagrams.
Here are some stencils that might help: