Google is taking its highly popular Gmail service to mobile phones, announcing a partnership with Sprint for a new handset version of its multi-functional e-mail and messaging client.

Google is giving the application away for free, and although Sprint is officially embracing the application, it is a Java-based downloadable application that can be accessed by T-Mobile, Cingular and other operators’ customers with mobile-browser-enabled devices. The application comes with many of the desktop features of Gmail, including the ability to organize email exchanges to conversation threads, email search, and synchronization back to a desktop client.

Google is rather late to the mobile e-mail business, its competitors AOL, Yahoo and MSM having all dipped into the space using client software from Oz and other providers. Google appears to be taking a different approach, however, making the service less tied to the operator. The Oz email services are usually tied into carrier messaging plans, charging customers per message or encouraging to sign up for messaging buckets, which often include SMS, IM and other message services. Gmail’s client, however, appears to act as a separate application, accessing the mobile Web independently to download message data. While carriers collect revenues from the bytes traversing the mobile networks—or revenues from unlimited data plans—the per-message charges don’t apply.