How to find details of Sharepoint installation programatically?

I need to find out some general background information about the Sharepoint installation on the local machine using C# - what sharepoint version/patch version it is and so on. Does anyone have any pointers on how to do this?

From stackoverflow

• It turns out that the way to find this, for MOSS at least, is checking the registry, specifically:

  SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0
  

  That includes a Sharepoint and a Version key that indicate sharepoint is installed and what version it is. Of course, the existence of the key at all is a pretty good indicator that Sharepoint is installed.

• SPFarm.BuildVersion

  http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.administration.spfarm.buildversion.aspx