Nimbuzz Messenger has more than 105 million users worldwide, but chances are good that you’ve probably never heard of it. The reason? Most of those users are accessing the app via Symbian.

While Nimbuzz only has 9 million users in the United States, the app is exceptionally popular in emerging markets and is one of the top three Symbian applications downloaded in the world.

Nokia has taken notice of the app’s popularity, and hopes to replicate it on Windows Phone, helping to launch a new Lumia-optimized version of the app Thursday.

For the launch, Nimbuzz developers were provided direct developer support from Nokia for the build as well as design assistance. While the app was already available in the Windows Phone Marketplace, Thursday’s update has optimized graphics and performance specifically for the Nokia Lumia series of devices.

“Nimbuzz has experienced incredible success on Nokia Symbian devices in the past, and Nokia saw a clear opportunity to assist us in bringing Nimbuzz to Lumia users around the world,” Joby Babu, Head of Operations at Nimbuzz told Mashable. “Through bringing their most popular applications from Symbian to the Windows Mobile Platform, Nokia is looking to replicate on their past market successes."

In addition to providing Nimbuzz with developer support, hardware, and design direction, Nokia and Microsoft will also actively promote the Nimbuzz application throughout their marketing channels.

“Nimbuzz has long been one of Nokia’s most requested apps,” Maximilian Schierstädt, Director, Global Partner Management, Nokia said in statement . “Nokia devices deliver outstanding experiences to consumers, and we’re committed to developing partnerships, such as Nimbuzz, which deliver even better apps, services and features to our portfolio of devices.” Nimbuzz, which provides features such as free SMS messaging, group messaging, and picture sharing, isn’t the only app Nokia has its eye on.

Babu says Nokia identified the top 10 apps currently within its ecosystem, and has offered development and design support to those apps in order to help them take full advantage of the hardware and software of the Lumia line. Nimbuzz is a model for what that support looks like.

Since the 2007 introduction of the iPhone, Nokia has lost 90% of its market share. The company announced it would adopt Microsoft’s smartphone operating system in 2011, giving up the homegrown Symbian in an attempt to regain its role in the mobile market.

Nokia will be holding an event in New York City on September 5th where it is expected to announce the newest addition to its Lumia line of smartphones, a phone that will likely be running the next-generation of Windows Phone: Windows Phone 8.

Do you think offering support for top Symbian app developers will help grow Windows Phone? let us know your thoughts in the comments.