WordPress Mysql connection problems - User/Pass/DB are OK

[manekineko]

Hello
I'm having problems with MySql and Wordpress.
Even if I copy/paste information about server (localhost), user, database and password, I'm having this message "Error establishing a database connection"
Database and User are already created with the right password.
I know there's some issues with Mac and PHP/MySql. A couple of friends were trying with same results.
I have Snow Leopard MacOS.
Thanks in advance