I had major problems with installing MAMP and WordPress on Mac OS X Snow Leopard. I was migrating from one MacBook Pro to a new one. As a web designer I had a lot of sites on my local system and needed to migrate them across to the new laptop. The pressure was on because my company wanted me to continue working as normal, install the new laptop and hand the old laptop as soon as possible to be given to a new person quietly waiting for it on the other side of the office. As he did not even have a system to surf the internet I would class this as extreme pressure.
Installing MAMP was super easy, but installing WordPress databases and installations was a nightmare. In the end I had to result to separate databases all using the root user for access.
I detailed the whole process on my blog: Mac OS X Snow Leopard: Install Local WordPress using MAMP if your interested. I keep having this same problem with MAMP.
If anyone can solve the issue of local host usernames on MAMP’s mysql I would really love to know it.