When I add a new user to my system I set a password and tell it to the new user. If the user doesn't like it, he/she can change it. However in my opinion it is better to force the user to change his/her password at the first login. Is there a way I can do that in Ubuntu?
You can just expire that password. After creating a new user
foo, just type:
sudo chage -d 0 foo
And he will be forced to change it after first logon.
Another option would be to expire the password using
sudo passwd -e username