Apple has released a document with the details on what things have changed in their MobileMe service for the iPhone.
Some of the changes listed in the document are as below:
Compose window address selector shows all email addresses for contacts, not just home and work addresses.
Newly added email addresses to Contacts appear in the compose window selector without having to logout and login.
Improved printing of HTML formatted messages.
vCard export supports all text fields.
Improved results when searching with both first and last names.
Improved Japanese name ordering.
This is a surprising move by the company as they usually reveal little about the updates to their products.