Scripting mesh edits

Like many others I am basically brand new at this. I would like to learn how to manipulate verticies just before game time. Its ok if its not the fastest process. More specifically I’d primarily like to make an automated process which cuts a slice from a mesh along a plane, but any insight into how to manipulate vertices would be excellent.

http://unity3d.com/support/documentation/ScriptReference/Mesh.html

Hmm, how would I go about printing vertex coordinates to the console?