How to determine the value of termination resistor?
I'll assume you're talking about a trace on a pcb so you're looking at either a strip line or a microstrip.  The basic impedance is a function of the trace width, the distance of the trace from it's reference plane, and the type of dielectric material between the trace (FR4 for example).   

Try one of these calculators http://www.eeweb.com/toolbox/microstrip-impedance

If you are trying to match your driver to a line you'll want to find out the output impedance of the driver.  Then that plus your termination resistor should match your line impedance.

Your best bet is to try to consult the datasheet, or ask your vendor.  Otherwise if you have access to sim models you should be able to extract.  If you happened to have a tdr lying around you could measure it :)

You could also find by connecting a known resistor to gnd and driving the driver high.  If you can measure the current used you can use Ohms law to calc the source impedance.  You can that in spice too.

Good luck