More than 80% of US households use mobile phones and 60 million digital music devices have been sold there in what Ford called a "flourishing market".
The agreement is part of a constant quest by Microsoft, the world's largest software maker, for fresh markets beyond the home and office computer ones which it dominates.
Ford, meanwhile, hopes that new technology will help it solve the problem of dwindling market share even in its home US market.
Other car companies are developing in-house technologies, such as General Motor's Onstar system.
The Sync system develops technology Microsoft already provides to carmaker Fiat under a similar deal outside the US.
