My car is about 100 miles away and I need to buy a new abs module for it, but I'm not sure of the part number or what other cars I might be able to find one on if I go to the junkyard.

Its 1999.5 A4 quattro 5spd AEB 1.8t..

 

use this company they will rebuild yours

http://www.modulemaster.com/en/index.php

you can drive without the module btw

 

There were many variations of the ABS module, all with different part numbers. From my experience different part numbers are not interchangeable, and I haven't seen anywhere that lists ABS module part numbers based on year.

ECS Tuning lists some of the various part numbers and the VIN numbers that go with them. Not sure how accurate this is, but worth a look:
http://www.ecstuning.com/Audi-B5_A4-...T/Braking/ABS/

 

I can tell you that none of what they list for ABS modules is whats in my sons 96 2.8 12V Quattro. All of their part numbers start with 8E, his starts with 8D ends with 111B and its one of the non rebuildable units. His is a January of 96 built car.