General plugins

Hi ,
I am working on a drupal module that integrates drupal with moodle using web services that moodle supports , the problem is I found it hard to implement SSO with these two.
I suggested a way to use cookies , for example I should open my drupal site , I login to the site , now I should go to my moodle site and find my self in .
I am stuck on generating the content of the cookie that should be created when I login to drupal. any hint or kind of code ?? e.g :
function generatecookie(username,pass){
   // do some thing and set cookie
}

Thanks in advance.