We are using SalesForce ourselves at Lightning Tools so it was an interesting project seeing how to integrate it with SharePoint 2007 and the Business Data Catalog. We’ve just published a free ebook that walks through how to do it in detail by creating a custom WCF web service layer. We’re also giving away the source code and we are hosting a dummy web service for you to even try out. You can get all the details you need from here:
We’ll be doing some more integration walkthroughs soon. If there’s a particular web service you’d like to see integrated please let us know.