With the recent update of the Web Help for SolidWorks 2010 SP04, we have now added access to the API Help documentation to the Web Help. Simply go to http://help.solidworks.com and select the "API Help (English only)" link as shown below.
Note that as has always been the case, the API documentation is only available in English and not localized into other languages.
With this update, users of the API documentation can benefit from the features of Web Help, especially the enhanced search capabilities.
Please note that when you use the API Help menu item from within SolidWorks 2010 SP04, it still links to the local help file so you can only access the API Web Help by manually browsing to http://help.solidworks.com in a browser. The API Help menu item will be changed to use the Web Help (when enabled through the "Use SolidWorks Web Help" option in the Help menu) in a future update; likely SolidWorks 2010 SP05 and SolidWorks 2011.