Amid its frenetic rush to reorganize around Windows Phone 7, Nokia on Thursday said it is selling its carrier-branded messaging service to Synchronica for $25 million in cash for the assets. Synchronica will also issue Nokia warrants for 18.3 million common shares in Synchronica.

Synchronica is a developer of next-generation mobile messaging solutions with a customer base that comprises more than 80 mobile operators and eight device manufacturers worldwide. When combined with Nokia’s 10 operator contracts in North America, Synchronica’s total addressable market across all operator customers worldwide will extend to 1.8 billion end users.

Synchronica said Nokia’s operator-branded messaging business, which provides white label mobile email and instant messaging services to operators in North America, will provide it with a complementary mobile messaging business and a strong foothold in North America.

“This acquisition marks a key milestone for Synchronica as we move closer to our goal of becoming the leading global player for next-generation mobile messaging. Nokia’s successful and highly complementary operator-branded messaging business will at a stroke transform Synchronica’s scale, profitability, and geographic scope,” said Carsten Brinkschulte, CEO of Synchronica, in a statement.

As part of the deal, Synchronica and Nokia will enter into a long-term relationship in which Synchronica will provide the messaging software which Nokia will continue to pre-load on Nokia Series 40 phones.

Synchronica also will assume responsibility for development, maintenance and support of the Nokia Messaging software that currently ships on Nokia devices and the gateway functionality for both Series 40 and Symbian devices.

About 250 employees, externals and contractors are planned to transfer from Nokia to Synchronica.

Synchronica says it plans to continue to develop the Nokia’s messaging platform and to merge it with its existing products, including the Synchronica Mobile Gateway.