It depends on what they are bringing in. If it is a dedicated line it could be very expensive to bridge off of that. If ATT is installing a VRAD (node), they are designed so that anyone can tap off the node. You need to be within about a half mile of the node.
What speed ate you getting now? ATT fiber optic varies widely in what is available. In Austin you can get 300 mbs and even their 1 gig ps service. In some areas only 10 or 10 mps is available.
Here is explanation of what could be available:
"The first flavor, the flavor that everybody wants is a 100% pure fiber installation that terminates at one of the subscriber's home external walls. This version is called FTTP/FTTH fiber-to-the-premises or fiber-to-the-home and it is used only in brand new and affluent subdivisions and not in existing dwellings. AT&T doesn't say what percentage of their uverse customers are on 100% pure fiber (FTTH/FTTP) but estimates place these numbers at less than 5%.
The second flavor, the flavor that everybody will get is called FTTN fiber-to-the-node and is fiber to a distribution device called VRAD (video ready access device) and from the VRAD to the subscriber's home using existing twisted pair copper cables... in short phone wires. The very same cable type that Alexander Graham Bell used more than 100 years ago when he first 'invented' the telephone, the very same corroded and decaying cables that everybody have in their homes today.
The third flavor, the other flavor that everybody will get is ADSL2+. AT&T is secretly and silently pushing this version of uverse and hoping their users will not notice the difference. AT&T is promoting this new flavor under the very same uverse brand as VDSL. Uverse ADSL2+ a much lesser version of uverse FTTN (VDSL) ?"
The first question you need to know is what they are bringing in. That determines what might be available to you.
If it is typical 10, 20 or 30 mps might not be worth it, but if it is the 100, 200 300 mps, or even the Gig service it would blow you away.