This morning I see that the bits for Exchange 2003 SP1 have hit the web (download here). This is excellent news, as SP1 has lots of great new features you want (this list taken from the announcement page, linked above):

• Enhanced security
• Updated deployment tools to make Exchange Server 5.5 upgrades and site consolidation even easier
• New language support for Outlook Mobile Access and Outlook Web Access spelling checkers
• Enhancements to the Outlook Mobile Access user interface that include out-of-office modification, a larger text entry field, search folder support, and improved menu navigation
• Co-existence and migration support in a new Active Directory Connector and IBM Lotus Notes R6 Connector
• Updates and improvements based on your feedback

Plus, there's a handful of cool, new “Web Release“ tools available (Note: this is not an exhaustive list):

• Exchange Domain Rename “Fixup“ - fixes your domain after a RENDOM domain rename so Exchange 2003 will work again. Have a look at this upcoming webcast for more details.
• Exchange 2003 Management Pack Config Wizard - GUI config for MOM Exchange Management Packs
• Outlook Web Access Web Administration - Web interface to configure Outlook Web Access server settings.
• Exchange Server Profile Redirector - Updates Outlook profiles at the client-side to facilitate cross-site or cross-forest mailbox moves
• Updated Exchange 2003 Deployment tools - Now has steps to walk you through cross-site mailbox moves!
• AUTD Binding Cleanup - easy cleanup of the Always Up-to-Date bindings
• Auto Accept Agent - Automatically processes meeting requests for resource mailboxes
• Badmail Deletion and Archiving - Automatic cleanup of the badmail folder for SMTP
• E-mail Journaling Advanced Configuration - Utility to configure additional archiving features

And, of course, one that lots of folks have been waiting for -- the new Intelligent Message Filter (IMF). You can also get the new MOM management pack for IMF. See more about IMF here, and in particular, read the IMF Deployment Guide.

Also, several “technical library guides” have been added or updated for SP1:

• What's New Guide
• Planning Guide
• Deployment Guide
• Administration Guide
• RPC-over-HTTPS Guide
• Exchange 2003 Management Pack Guide
• Exchange 2003 MP Rules Technical Reference

Whew... That's a lot of links. Enjoy!