This might have gone unnoticed, but Exchange 2003 Online Help was updated for SP1 too.
This update includes additional topics that were not included on the product CD.
The Exchange 2003 Help is designed to assist you in day-to-day administration of Exchange. Use this documentation to guide you through Exchange features, tasks, and administration procedures. The Exchange Help augments the online articles, books, and release notes about Exchange 2003. It provides all the important conceptual and procedural information you need after you deploy Exchange.
You can get it here:
Thanks to Susan Bradley, SBS MVP for the idea to blog this! :)