I downloaded MAMP, downloaded WordPress, and started doing the setup for a local server to play with WordPress.
When I clicked on the PhpMyAdmin tab to continue with the localhost setup, suddenly the screen came up with something like "PhpMyAdmin appears to be out of date. You need to upgrade it before continuing". I looked, and found long technical pages with no easy guide to upgrading PhpMyAdmin. I tried just downloading the latest PhpMyAdmin folder and copying that over the PhpMyAdmin folder in MAMP. It's now asking me for a username and password.... but I have not registered PhpMyAdmin to even have a Username or Password in the first place!
I went to the MAMP forums and was immediately put off by long lists of complaints that the MAMP forums are not really offering any support.
Then I found this link that suggested installing WordPress without MAMP.
But it's for Lion, and does not work in Mountain Lion.