This is exactly how I have most of my bills setup. I only get 2 bills a month in the mail, of about 10 or so. Not only does it save trees, but it's a lot less of a hastle to deal with it all.
Especially considering the ATT bills seem to run up to 50 pages. I think they are going to make the bills something that only comes by email though, unless you request it.
If nothing else, eliminating all the junk mail that is delivered would save a few trees as well! Ads for auto insurance, credit cards, grocery store sales papers.....the list goes on.