salt/hash passwords

[XFSIllusion]

i need to create a form so my members can register outside of my forums, from my site. i know how to query the database etc. in PHP, but i'm having problems with the passwords. i know the query uses MD5('pw', salt), but i need help with using the salt part of it. i need code so i can create a form asking for username and a password, after the user submits it, it will search for the username and password they entered...however, the salt function is confusing to me. how do i set up the function to do this? i'm looked at the login.php, but its so huge i dont know where to start to be honest...i only need the part to find a record based on the password. any script or info on this would be helpful, thanks.