Google Email Uploader (Windows)
Source: Google Code
The Google Email Uploader is a desktop utility for Windows that uploads e-mail and contacts from other desktop e-mail programs (like Microsoft Outlook) into your Google Apps mailbox. The Email Uploader preserves information such as sent dates and sender/recipient data, as well as the folder structure used by the other e-mail program. The Google Email Uploader requires a Google Apps account. The Email Uploader is Apache 2.0 licensed open source software, and is governed by the terms of the included license file. This means you may modify the tool to better suit your needs.Version 1.1 adds support for contacts.