Official score  reporting to colleges is necessary when you have not reported scores at the time of the exam. There are two main methods to report your GRE score to colleges. One is through Fax, other is through phone. Always Reporting via phone is better than reporting of scores by Fax. Reporting via phone is always easy and faster. Here are some instructions for successful handling of GRE score reporting visa phone.

Before calling ETS, get the below ones:[From your GRE score card]
Your GRE test registration number (comes on the score card)
Your GRE test date.
Your Birthday Date.
Your College codes and Department codes (http://www.ets.org/Media/Tests/GRE/pdf/gre_0708_tclist.pdf ). Suppose you want to report to NCSU and Clemson univ. for MS in

    Mechanical Engineering, you would have different GRE codes for NCSU and Clemson university. Also you need find the department code for the mechanical engineering.
Your credit card number and it’s expiry date (American Express, MasterCard, or VISA.etc..)
A touch-tone phone [may be your landline or mobile...u need to press the phone buttons for entering all the details.]

STEP by STEP Procedure:

Make a call to the phone number mentioned on the below website. Via  phone u can send scores to 8 universities at a time. If you want to send score for more than 8 universities  u need to call again.

Click here to view the phone number to call to report scores.
You listen some instructions first. It will ask to to press some number [it may be 1 or 2] on you phone for additional score reporting.
There after they ask you to enter your GRE test registration number.
Then your Test Date (they will ask for month and last two digits of the year of your test date. Example: If your test date is Jan,2007 you need to enter 0207)
Then enter  ask for your birthday as in the format asked.
Now enter the code of the college you want to apply. then enter department code. Repeat this for all colleges for which you want to send scores.
After you are done with the college it will ask for credit card number followed by expiry date. enter the 16 digit card number and expiration date. Take care while enterin the credit card information.

    If your credit card details are wrong they won't process you request and your scores will be pending for a longtime which is a tough issue to solve.
At last u need to drop the call after everything is over i.e when it says good bye.