from Here:

We've received information about future enhancements for Office 2003. Office 2003 SP1 which is currently planned for release in late May will include fixes/improvements for all applications in the Office 2003 suite with some big enhancements for InfoPath 2003.

Microsoft are adding the ability for custom controls, active x controls that can be made available in InfoPath's control tasks pane as well as other improvements throughout InfoPath. Details are unclear on what enhancements will be made in other applications like Word and Outlook at the moment. See below for the InfoPath improvements. Details for other Office applications coming soon.

Screenshot: InfoPath 2003 - Tools Menu
Screenshot: InfoPath 2003 - Custom Controls
Screenshot: InfoPath 2003 - Add Custom Controls
Screenshot: InfoPath 2003 - Form Options
Screenshot: InfoPath 2003 - User Roles