In the general tab you just make up a name for the database connection. This mostly matters for people who connect to multiple databases. Make something up.
In the connection tab use Server=localhost, port=3306, connection-type=direct. The fields should have defaulted to this (except, perhaps, the server field).
In the login tab, use user=root and leave the password empty, unless you assigned a root password when you installed MySQL. Previously, you had to leave the password blank, but Rails now supports the new MySQL authentication scheme so you *can* use a pssword now. If you check the "Save Password" box it won't ask you for the password everytime. Just leave the database field empty.
That should do it.