I was reading Nikodemus Siivola's excellent Common Lisp FAQ and came across a reference to Jonathan Fischer's guide to getting started with Common Lisp on OS X. If you're an Machead who's wanting to get started with CL, these instructions will help a lot. Fischer outlines his plan as
The rest of post expands on the individual steps of the outline.
My only quibble with Fischer's plan is the recommendation to use Aquaemacs instead of GNU Emacs. I've used Aquaemacs and it's a great tool but I much prefer GNU Emacs. Perhaps I'm not enough of a Machead to worry about having the Emacs UI modified to do things the Mac way but I like using the “standard” Emacs because it's always more up to date and because it's available and works the same on all the platforms that I use.
In the comments, Greg Pfeil makes the case for Clozure Common Lisp as easier to install and having an IDE for the Mac. I've used CCL and it's definitely a great CL implementation. I use SBCL because it's used by many of the Lispers I admire and follow and seems to be preferred by most experienced Lisp hackers. The integrated CCL IDE holds no attraction at all for me. As I've written before, I'm all about using and mastering a single editor for ALL my work. In fact, my original impetus for moving from Vim to Emacs was to get Slime so I don't need no stinkin' IDE. Again, though, I used CCL for some time and I can recommend it without hesitation.
If you've been wanting to try out CL but it seemed too hard to get started, Fischer's post may be just what you need.