The VoIP acquisition is Microsoft’s second: In late August, it acquired VoIP software developer Teleo Inc, which gave Microsoft the ability to add VoIP services similar to Skype’s, such as making calls from a PC to traditional phone lines.

Microsoft’s latest move is more of a business play, enabling the company to launch VoIP applications designed for SME and enterprise use. The latest deal also is part of Redmond’s strategic move into online services known as the Live Software program.

Microsoft plans to include media-streams.com’s VoIP technology in Microsoft Office, specifically in the real-time collaboration platform it is building for Office through its Live Communications Server software. One potential application would be the ability to make VoIP calls or launching VoIP conferences directly from contacts or e-mails in Outlook.

Microsoft said it intends to use media-stream.com’s technology, expertise and intellectual property in an effort to create a unified communications system that will encompass email, voice telephony, text messaging, instant messaging, and audio, video and web conferencing.

We’re excited to join Microsoft’s Real-Time Collaboration Group and focus our technologies and people on delivering Microsoft’s vision for unified communications to dramatically improve collaboration, said media-streams.com CEO Erich Gebhardt.

This bundling of VoIP technology into commonly used software applications such as Word, Excel and PowerPoint will no doubt remind many of Microsoft’s decision to bundle a web browser (Internet Explorer) with its operating system in the 1990s, a move that arguably led to the demise of then market-leader Netscape Communications.

Of course, Microsoft is not alone in its quest to capitalize on VoIP. During the past several months, AOL, eBay, Google and Yahoo all announced major plans for consumer VoIP. eBay’s purchase of Skype for $2.6bn in October was seen as a catalyst. But few, if any, of these plans have yet to materialize and some industry insiders believe a bubble of sorts of forming.

Still, by integrating VoIP with Office applications, Microsoft likely will help shift the general perception of VoIP from being a cheap-calling consumer technology to more of a business tool.

Microsoft’s move into the space is sure to stir cause concern among Microsoft’s competitors, as well as attract the scrutiny of the US and EU regulators.

It is understood that Zurich, Switzerland-based media-streams.com will become part of Microsoft’s real time collaboration unit, which is headed by Microsoft VP Anoop Gupta.