Google is battling strong to be the preferred online collaboration tool with Google Apps and they might just come out ahead with these latest offerings. Google will make available mail migration, allowing administrators to transfer mail from an IMAP server into exiting Google accounts.

Aside from that, Apps will also feature the following:

• Shared address book - Users who want to add colleagues to a new email or document no longer have to go to a separate list or company directory. Users can search through all the users on a domain by clicking the “Choose from contacts” link.
• Google Docs & Spreadsheets charts - Number-crunchers will be happy to see that we’ve included the ability to create charts in a spreadsheet.
• Increased Gmail attachment size - We made it easier to share more of those large presentations and files as attachments by doubling the allowable attachment size to 20 MB to make Gmail space even more useful.
• Multi-user chats - Now users can invite multiple contacts into the same chat on the Google Talk gadget from their Start Page. This will be useful for small groups working on a document or other project together.
• Google Docs & Spreadsheets refresh - Soon we’ll complete a visual overhaul of Docs & Spreadsheets that will make it much easier for users with dozens or even hundreds of documents to search, locate, and organize their documents.

Check out Google’s press release about the new features.