Microsoft closed off the acquisition of VoIP service provider Skype for a massive $8.5 million – the software maker’s biggest acquisition to date. Microsoft got the green light from the FTC in June, and now the European Commission also gave its approval. Skype head Tony Bates will become president of the Microsoft Skype Division, and will report to Microsoft chief executive Tony Bates.

Here’s a part of the EU’s statement:

“The European Commission has cleared under the EU Merger Regulation the proposed acquisition of the Internet voice and video communication provider Skype by Microsoft Corporation because the deal would not significantly impede effective competition in the European Economic Area (EEA) 1 or any substantial part of it.”

Now that Skype is a part of Microsoft, the latter plans to incorporate the brand name into a lot of its consumer devices, something that’s seemingly been on the up and up these past months anyway.  One of the first priorities will be to develop a mobile app for Windows Phone 7, according to Skype vice president and GM of products and marketing Neil Stevens. The app will have deeper access to the mobile OS, too, Stevens said.

Another big development is Skype’s updated integration with Facebook, announced shortly after news of the merger with Microsoft surfaced.  The company has already added a Facebook plugin built on its REST API to its desktop app, but scaling to be able to support the hundreds of millions of Facebook users turned out to be a challenge for Skype’s engineers.

Microsoft intends to bank on Skype’s existing portfolio and sheer popularity to boost its own offerings, but there are speculations of other plans in the works. Technologist Kevin Fox even suggested that the software maker may try to create a closed ecosystem where it controls the hardware, software, and the data plans.