// Returns Jan 31, 2012
myDateTimeObject.ToString("MMM dd, yyyy");

// Returns 31 January, 2012
myDateTimeObject.ToString("dd MMMM, yyyy");

Console.WriteLine(DateTime.Now.ToString("d-MMM-yy"));

Console.WriteLine(DateTime.Now.ToString("d-MM-yy"));

Console.WriteLine(DateTime.Now.ToString("d-MM-yyyy"));