Learning a little Emacs Lisp is not that hard. Emacs does its best to help you learn its lingua franca. So, how can you learn Emacs Lisp?
Use ‘C-x ESC ESC’ to repeat commands you execute, and look at the Emacs-Lisp code that executes them, before hitting ‘RET’ (Return) – see RepeatLastCommand.
Use ‘C-h f’ (‘describe-function’) and ‘C-h v’ (‘describe-variable’) to understand commands and variables you use. In the help description, click the function or variable name (link) to go directly to the source code that defines it. Try to read the source code. When you want to know what some function you see used does, use ‘C-h f’ on it… Got it?
Use ‘C-h k’ to see which commands you are executing when you use keys. Then follow the previous bullet: click the name (link) of the command to see its source code…
Read the Emacs Lisp Introduction: EmacsLispIntro. Use ‘C-h i’, then choose `Emacs Lisp Intro’. You can also read this manual on the Web.
Read the Emacs Lisp Reference manual: EmacsLispReference. Use ‘C-h i’, then choose ‘Elisp’ (Emacs Lisp is sometimes called “Elisp”). You can also read this manual on the Web.
SteveYegge’s intro to the language: 
Mitch Fincher’s 50-point summary of the language: 
Pascal Costanza’a intro to Lisp (in general, not Emacs Lisp): 
Paul Graham’s overview of Lisp (in general, not Emacs Lisp): 
Paul Graham’s book ANSI Common Lisp, chapter 2 (Common Lisp, not Emacs Lisp): 
Peter Seibel’s book Practical Common Lisp (Common Lisp, not Emacs Lisp):