Hi suchi,
You can just register for teh exam online thro prometric web site at
www.prometric.com The site is very self-guiding and I am sure that you can be able to register for the exam in less than 5-10 mins
I am sure taht you dont have to call any 1-800 numbers!!
You would first have to choose a center that is close to you (Prometric gives you a list of centers based upon the state that you choose ) and then you can purchase the exam directly!!
If you have any specific problems or questions, let me know
Good LUCK !!!:-)