Yahoo! CEO Carol Bartz, and President and CEO of Nokia, Olli-Pekka Kallasvuo, were on hand at a press conference in New York today to announce a partnership between the two companies.

As part of the alliance, Nokia will be the exclusive, global provider of Yahoo!’s maps and navigation services, integrating Ovi Maps across Yahoo! properties, branded as “powered by Ovi.” In turn, Yahoo! will become the exclusive, global provider of Nokia’s Ovi Mail and Ovi Chat services branded as “Ovi Mail / Ovi Chat powered by Yahoo!”

Nokia and Yahoo! plan to work on swappable IDs between their services, beginning by allowing people to user their Ovi user IDs across select Yahoo! properties to access Yahoo!’s online content and services.

Bartz said that partnering is “increasingly a part of Yahoo!’s” DNA, adding that Nokia’s Navteq mapping assets will offer Yahoo!’s users a much richer experience.

Kallasvuo was hopeful that the new partnership will help Nokia create inroads with a customer base in the United States. 

“As we continue to roll out more of our services and devices with U.S. operators, we expect this alliance will be crucial in growing Ovi services across mobile and the Web,” Kallasvuo said.

According to a press release, the co-branded service offerings are expected to become available from the second half of 2010, with global availability expected in 2011.