Skype has announced that it now has over 100 million users worldwide. The company achieved this milestone in just two-and-a-half years, and has nearly doubled in size from September 2005 when it had 54 million registered users.

“Passing 100 million registered users within such a short time reinforces how much people love how easy Skype makes it to call friends, family and colleagues all over the world for free,” said Niklas Zennström, CEO and co-founder of Skype.

“We owe the Skype community a debt of gratitude for helping us realize this exciting milestone and look forward to keep growing together.”

The company, which was bought by eBay last year for $2.6 billion last week announced it is to start selling Ringtones from bands such as Red Hot Chili Peppers and Madonna.

In its latest move, the internet telephony company owned said that it has signed licensing agreements for world-wide distribution rights to potentially hundreds of thousands of musical works as ringtones for Skype.

The company is hoping that today's agreements will also pave the way for agreements with additional music recording companies.

In the coming months, consumers will be able to download master ringtones from WMG artists including Madonna, Green Day, Red Hot Chili Peppers and many more to Skype for play back when Skype users receive incoming calls.