send login details in email alerts

currently, my users register via facebook/google / twitter on easyfriends.com and usually cannot recollect the random passsword generated by dolphin. hence, they dont come back often to easyfriends. can anyone store this random password so generated in dolphin and send login details to all users in email alerts?  Alternatively, just put a link so that users can directly login from their email alerts?

awaiting reply,

ceo of easyfriends.com, contact@easyfriends.com, india