I realize that picking on AT&T is easy, but the company regularly manages to reach new heights of terrible service that betray its general attitude toward its customers, which is more or less like that of a parasite to its host.
Consumerist has an interesting piece of the $10/month DSL plan that AT&T is required to offer under the terms of an agreement with the FTC. They are "offering" it in the sense that it exists as a hypothetical service. However, they seem to making it impossible to actually sign up for it, and if you have trouble on the web site - as everyone in the comments seems to - don't call them or email them; they won't talk to you.
From a legal perspective, I think AT&T is just begging for a class action lawsuit from an aggressive AG in one of states where they do business, because this is starting to smell of fraud.
From a marketing perspective, it's even worse; who wants to do business with a company like this? (I do; they're our local telecom, so I have a bare-bones land line from them, mainly for my house's alarm system and for dire times like hurricane season; I also have a mobile phone from them. Cingular always gave me good service, but I am afraid that the AT&T virus will now infect them.)
If you treat your customers like you hate them, like you can lie to them and charge them extra for no reason, they will find options: VoIP services, cable internet, and so on. They won't be so eager to buy your new digital TV service or your cell phones. And when you keep misrepresenting yourself and failing to live up to agreements with the federal government, sooner or later that will come back and bite you.
I'm old enough to remember the breakup of the old AT&T. Now that the company has become so large and powerful and, at the same time, abusive, the logic of that breakup is starting to resonate again.