These PDFs are amazing, when i was studying for VCP 4 I used these religously. They leave nothing uncovered and are very useful in a pinch. The documents contain commands, maximums, definitions, you name it, its there! I have also included links to other great references.
Click herefor the vSphere 4.1 Reference Document. Once there, just click on “here is the vReference card updated for vSphere 4.1.”
Click herefor the vSphere 4.1 Firewall Diagram
Click herefor an ESXTop Reference Credit card.