The Many Faces of an Undying Programming Language
An article that goes over the various types of Lisp; nice high-level view.
SLIME reference card
Handy reference card OF SLIME commands.
Lem
A programmer's editor written in Common Lisp, written for Common Lisp, which aims to be a good Common Lisp IDE; but which also works as an IDE for other languages too.
Think Emacs in Common Lisp.