This collection of OSI model & networking aids applies to the Network+, & A+ exams. Most OSI model & networking aids—particularly the OSI Model Guide—also apply to Microsoft's 70-642 exam and any others that test on basic networking knowledge.
OSI Model Guide
This table outlines the OSI model.
Another look at the OSI model is the OSI model map from Protocols.com. It's more extensive than my OSI Model Guide and links to descriptions of each protocol. However, their OSI model map does lack 2 features of my OSI Model Guide—port numbers and hardware on each OSI model layer.