I happened upon an interesting problem today whilst setting up WordPress 3.3.2 on MAMP. Essentially WordPress plays nicely with MAMP so long as you don’t want to switch on the Network feature that has been rolled in to the WordPress core since version 3.0 (it was previously available as WordPress MU (Multi User).
The problem is a result of WordPress Network’s inability to handle a host name with a specified port number. By default, MAMP uses port 8888 and 8889 for Apache and MySQL respectively, resulting in the host name http://localhost:8888 which WordPress Network won’t accept (the setup discussed here fails when using a host name that has a port number appended to it). However, with a few simple config changes to MAMP and and some very minor tinkering on the command line, you can overcome this problem.