Skype launched an updated version of its Internet telephony software yesterday, adding call forwarding and personalization options to its popular VOIP (voice over Internet Protocol) service.

Skype's update is currently only available for Windows users, although the company says it is working to bring the new features to its Mac, Linux and Pocket PC editions.

Skype version 1.4, which launched for beta testing in August, allows users to forward incoming Skype calls to another Skype name or to other landline or mobile numbers. Calls forwarded to Skype names are free; calls sent to traditional phone numbers are changed at Skype's SkypeOut rates, which start at €0.017 ($0.02) per minute.

The new version also introduces "Personalize Skype," a customization service being managed by Qpass, a Seattle-based Skype partner. Personalize Skype offers customers pictures to use as avatars and sound clips that can be used as ringtones or to replace Skype's default sounds. Most pictures and sounds are priced at €1, although a limited number are available for free.

Qpass will handle content acquisition and billing for Personalize Skype, a service it manages and hosts. Qpass' list of customers taking advantage of its add-on ringtones, images and mobile games offerings include Cingular Wireless, T-Mobile International, Vodafone and Sprint Nextel.

Earlier this month, Luxembourg-based Skype agreed to be acquired by eBay for around $2.6 billion in cash and stock. The companies expect the deal to close by the end of the year. Skype advertises a registered user base of 56 million, with more than 3 million people simultaneously connected to its service at any given time.