How do I add a reference to SharePoint 2007 from C#. What is the name and location of the DLL please?
You can find the dll here @ this location C:\Program Files\Common Files\microsoft shared\Web Server Extensions\12\ISAPI\Microsoft.SharePoint.dll, Adding the reference you need to right click Reference in the VS Project select the above location and add it.
The name of the base SharePoint DLL is
Microsoft.SharePoint.dll
and it's normally located in
c:\Program Files\Common Files\Microsoft Shared\web server extensions\12\ISAPI
If you are using source control, I would put your Microsoft.SharePoint.dll DLL into a seperate folder named something like lib, along with your other 3rd party DLLs, and add your project references to there. That way, when a developer gets the source code, the references won't be broken if their environment is set up differently.
When you are working with Sharepoint you should create a project with the correct type. The references will then be added automatically.