Mass email with login details

Hi Everyone,
I have a couple questions regarding login details. I have a client who wants to send an email to all users on their wordpress site with their username and password added along with other information. The issue is most of the users have never logged in before so they don\'t have a password as yet. So my questions are 1). Is there a way to send out a generic password to all for them to change to their own, or 2). Can I send the users straight to the change password page?, or 3). Any other solutions to help me out?
Cheers