You'll need to know things like the VPI/VCI addressing, whether the circuit is VBR, UBR, etc., encapsulation, etc. If your provider is competent, they should be able to provide you with a template for a Cisco router to get you started.
I'm sure you're looking for the "one size fits all" ATM interface configuration, but it isn't that simple. It all depends on what you really bought how the circuit will end up being used. Just IP data traffic? Carved up into multiple priorities, with some for voice, some for data, etc.? Is it a point-to-point ATM, or point-to-cloud? Will you be mapping frame-relay into the ATM (FRASI)? Will you be muxing multiple T1's into a single logical ATM (IMA)? Not as simple as frame or PPP, unfortunately. That's not to say it's HARD, just that you'll need to work closely with your provider to make it work properly. And again, I'd have every expectation that your provider can support you with an engineer that can get you going.
This link has lots of good ATM info for the 7200, including configuration examples.
http://www.cisco.com/en/US/customer/products/hw/modules/ps2033/products_implementation_design_guide_chapter09186a008019994d.html
HTH!
