Nine months after agreeing to purchase Skype for $8.5 billion, Microsoft Windows Phone handsets have a beta version of the audio and video chat service. The new, free beta is available directly from the Windows Phone Marketplace. Although the initial smartphones running Windows Phone didn’t offer front-facing video cameras, newer models are appearing, and the Skype beta does support video calling on these.

In addition to video chatting, the new Skype software can be used for voice-only calls and IM chats with individuals or groups. All of the supported Skype services work over 3G, 4G and Wi-Fi networks, although I’d be wary of using Skype for video calls on a mobile broadband network if you have a limited data plan. As a pre-release beta, there are many limitations as noted by Ed Bott: English language only, no support to run in the background and video calls are landscape mode only, to name a few. Bott says a more polished version is due out in April with the “Tango” version of Windows Phone. Regardless, the first Skype release looks well done in the Metro UI:

When Microsoft purchased Skype in May, I offered some ways the communications client could greatly benefit Microsoft’s Windows Phone platform: Namely, a more direct tie-in to carriers and the potential to differentiate the handset operating system with deep Skype integration. For now, you can’t manage Skype contacts in the beta client, but I’m sure that will change going forward and will have hooks into the People hub for Windows Phone.

Interestingly, while Microsoft has much to gain from the Skype purchase, Cisco may have mistakenly passed on buying Skype. Last week, Cisco’s CEO, John Chambers discussed why his company didn’t acquire Skype, which would have been a great pairing with Cisco’s networking technology. Now, Microsoft has the advantage because it can presumably integrate Skype’s software and services directly into its mobile and corporate communications platform. Perhaps that’s why Cisco has asked the EU to block the Microsoft – Skype deal. Cisco can only hope to support Skype services, which are available both for consumers and business organizations.

Regardless of Cisco’s hopes, I suspect that Microsoft’s Windows Phone sales will gain momentum through Skype’s services, the introduction of a new low-cost Nokia handset — the Lumia 610 — and Windows Phone Marketplace support in 23 more countries. The Windows Phone platform has a long way to go before it comes close to having significant market share, but as I said in 2011, it has a good chance to supplant BlackBerry as the no. 3 platform by the end of this year. The mobile market is all about momentum. Right now, Microsoft has it with improved software, capable new hardware and a growing number of available applications.

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