To find out your username:
Click Memberlist (see link above) you should then be able to find your username from the list.
To find out your email address:
Click Memberlist (see link above). Once you locate your username click on email to the right of this, your email address should be revealed.
Forgotten password:
At log in click Forgotten Password link. A new password will be emailed to the email address you registered with. Once you've logged on you can change the password if required by going into Profile (see link above).