Please, don't do that.
Storing passwords in clear text is a major security risk. Hash them instead:
Password Storage: How to do it.[
^]
Then when they forget their password, reset it to a random value (a GUID is good) and email them the new value. That way, you aren't sending the password to someone who has just picked up your laptop while you are out of the office...
A GUID is a good choice, because it is too long to remember easily, so it encourages the user to change it to something they can remember.