Ok ! .. one of my friend sent me offline message to get skype premium account for free !!
Here are the steps
Step 1 : Visit Skype Promotion Link
Enter your email address and check the box that says: “Tick this box to receive regular updates from the Skype Collaboration Project”.
Check your email. You’ll get a coupon code.
Step 2:Go to Redemption Page . Enter details and Voucher code and Enjoy 1 Year Free Skype Premium Account.
The voucher is valid to redeem till 30th April 2014 !!
If works , please notify in comment !!
https://collaboration.skype.com/promotion/ is not working. It backs to https://collaboration.skype.com/
It already expired !
Sorry for inconvenience.