To clarify the last post (I had to reinstall Visual Studio to be sure), the API Viewer can be activated by going into the menu Add-Ins -> Add-In Manager... then double-click on VB 6 API Viewer to load it, then you can also select the Load On Startup option at the bottom of the window. This will load the API Viewer whenever you are working.
To view the API calls, open the viewer: Add-Ins -> API Viewer
Then choose File -> Load Text File and select Win32API
See the MSDN for usage.