Get MySQL working, make sure you have MySQL header files and client libraries.

Install mod_rails.

Install the typo gem.  Apple put MySQL headers and libraries in /usr/include/mysql and /usr/lib/mysql which is not what the typo gem expects (/usr/local/mysql/{include,lib}).  It is therefore necessary to point the installer in the right direction, which we do by getting it to use the mysql_config program:

sudo gem install typo – –with-mysql-config=/usr/bin/mysql_config

Create a MySQL user, (e.g. sams_blog) that has privileges to create two databases: one for your blog, and one that has the same name with _test appended to it, e.g. sams_blog and sams_blog_test.

typo install /path/to/your/blog db_user=sams_blog db_name=sams_blog db_host=localhost db_password=<password>

Typo sets up the database, and starts a webserver running on port 4869.  Navigate to that page and create the first user (this will be an admin user).  At this point I stopped that server (using: typo stop /path/to/blog) and configured mod_rails to run it instead.