If you like the new SharePoint 2010 external list feature and the new Business Connectivity Services (BCS) and want to make use of something similar in SharePoint 2007 / WSS 3.0 to simply connect SharePoint lists (no web parts) directly to external data sources without any programming or tools, please take a look at:

 

 

All list features are available, e.g. grouping, lookups.
You can start buiness workflow actions in SharePoint, if external data changes.

The shareware version is completely free for download and use.