First of all make SURE you are on a land line telephone in a quiet area, so you wont be disturbed or cut off!
Next make sure you have a copy of your resume in front of you, and make any notes for yourself on it that you might need (phone numbers, actual experiences for particular jobs, etc)
Next get a note pad and be writing down important things that yall discuss!
And finaly on a sheet of paper, try and think of questions that they might ask and have some what of an answer thought of, because they will ALWAYS try and throw you a curve ball!
One question they always ask is "why do you think this is the job/position for you?" and another question that i have been asked more then once is, them asking you about something that you dont know how to do, or have a fault in, and with a question like that, make sure you have something in mind & some sort of way that you have thought of to help yourself over come that.
Hope this helps!