I would suggest this for the "initial" password - the students initials and date of birth.
- STUDENT NAME: Sally Green
- DATE OF BIRTH: January 14, 1977
- USERID: sallygreen (based on what you described)
- PASSWORD: sg011477
This will help to keep their accounts secure until they can signin and change their passwords. Would also suggest trying to get into a computer lab and go through the sign up process at that time with the entire class allowing them to sign in and make changes at the same time while you are there to help. This will cause less of a security problem with the passwords (less chance for students to try to sign into others accounts once they know the relationship between the username and password) and allow you to help them and be aware of login problems early on.
BTW, Zbigniew Fiedorowicz thanks for the bulk upload. I used it the other day and it was smooth although I did not add the groups field to it. The help file in MOODLE v1.2b needs to be upgraded to include the groups field.
Hope this helps Marc.