I am an ATT customer and I use WS_FTP to access my web pages (plural because to get 60 megs, you must have 6 email addresses, 10 megs per address) unless I am uploading just 1 file, then I use the http upload feature on the Member Services page. I suppose the lack of information provided by ATT can be frustrating for the non-IT people, but I am so used to being told incorrectly how to do it, that I just do it my own way, which is industry standard. The upload address is indeed
ftp://upload.attbi.com/ and your email address is your login and your email password is the password, but only for 10 megs. Each 10 megs will use the email login and password you create when setting up the additional email boxes.
If this didn't come out right, feel free to send me an email and I will try to clarify.