Simon,

1) .NET Framework has two classes that you can use to obtain the
information specific to files and directories. They are: FileInfo and
DirectoryInfo. Unfortunately, there is not a method on the
DirectoryInfo class to return the size of the Directory. I wrote a
little helper class that has a method on it that will return the size
of the directory in bytes. Here it is:

public class FileSystemHelper
    {
        private FileSystemHelper()
        {
        }
        // returns the size of the given directory in bytes.
        public static long GetDirectorySize(DirectoryInfo di)
        {
            if(di==null)
            {
                throw new ArgumentNullException("di");
            }
            long size = 0;
            FileInfo[] files = di.GetFiles();
            // sum up file size
            if(files!=null && files.Length>0)
            {
                foreach(FileInfo fi in files)
                {
                    size+=fi.Length;
                }
            }
            // sum up dir size
            DirectoryInfo[] dirs = di.GetDirectories();
            if(dirs!=null && dirs.Length>0)
            {
                foreach(DirectoryInfo dii in dirs)
                {
                    // recursive call
                    size+=FileSystemHelper.GetDirectorySize(dii);
                }
            }
            return size;
        }
       
    }

You can get to the contents of the directory by calling GetFiles() and
GetDirectories().

2) GetFiles() and GetDirectories() is overloaded to accept a
searchPattern so you can use that to exclude certain
files/directories.

3) I don't know of any open source tools that do this kind of stuff.

sayed

[...]

JDiskReport. Google for it.

            Burkhard