Verbatim is Mozilla's web based localization tool. This article is a SUMO oriented overview of the basic translation workflow. It also covers some additional tasks for people with approver privileges.
The Mozilla Verbatim site is located at http://localize.mozilla.org. If you have a Mozilla LDAP account you can just log in with your LDAP username and password. Otherwise, you'll have to register for an account before you can log in.
This is some additional information about the Verbatim interface:
Once you've translated some strings, you can push them to the VCS.