The Microosft SharePoint Products & Technologies Teamblog has published some good comparison information on the different editions of the platform :
1. What is new in Microsoft Office SharePoint 2007 compared to SharePoint Portal Server 2003?
2. Do you know the difference between the SharePoint Enterprise CAL and Standard CAL?
3. Do you know which edition of SharePoint includes Business Data Search?
A. Microsoft Office SharePoint Server 2007 for Search Enterprise
B. Microsoft Office SharePoint Server 2007 + Standard CAL
C. Microsoft Office SharePoint Server 2007 for Internet Sites
4. If you are a Content Management Server 2007 customer with software assurance can you upgrade to Microsoft Office SharePoint Server 2007?
How great would it be if there was a comparison of all the of the editions like there is in SQL 2005? Here’s a downloadable spreadsheet with all the differences (note the tabs). Thanks to Jeff for pulling this together.
The Microsoft Office SharePoint FAQ, the Version Comparison, and Edition Comparison a set of tools to help you better understand the difference between the 2007 editions of SharePoint and how they are licensed.