Businesses and other organizations moving from old mail solutions that support IMAP can use the IMAP migration tool, but for administrators currently on a non-IMAP solution, this API lets them build custom applications to migrate mail from any legacy system to Google Apps.

Editions impacted:
Premier, Education and Partner Editions

Languages impacted:
US English

How to access what's new:
Read more about the mail migration API in our developer guide. (see link below)

For more information:
http://code.google.com/apis/apps/email_migration/developers_guide_protocol.html