MD5 Password Login Driving me Crazy

For what ever reason I cannot seem to get a user to login using MD5. The user creates the password on log and it works fine, password encrypted and all. I test to see if the process is working ok on creation by using the UPDATE penpals SET password = MD5(password) and the encrypted passwords match. When the user goes to login into the page though I have the encrypted password echo to the page and they match except a 52 on the end of it which I am assuming is a space or something being picked up on submit or something. I recall there is a way to trim the field so that it doesn't pick up spaces but can't recall what it is. Anyone know what it is and if it could be that? Thanks