make a link to the "forgot password" and redirect it to another page where u ask the user to give his unique email id in text box (indicating the user that ur pw will be sent to ur email id) and submit the form.
then u check in ur database the password against that email id and send it to the email id of the user.
after the user got that he/she can access his/her account.
This the simplest way to deal with forgot pw
u can also give security question option and check for the correct answer...