I've written a method which will format any given string into a more readable phrase.
This method can be quite useful if you're generating your code or building your API based on an outer settings like a config file, DB, Reflection etc.

Code:

/// <summary>
/// Format the string so it will be more readable.
/// </summary>
/// <param name="field">The field to format</param>
/// <remarks>
/// Written by Oren Ellenbogen (23/01/2006) - parsing string AI for idiots ;)
/// </remarks>
/// <returns>Formatted field name</returns>
public string FormatField(string field)
{
   StringBuilder formattedField = new StringBuilder(field.Length * 2);
   for (int i = 0; i < field.Length; i++)
   {
      if (i == 0)
         formattedField.Append(field[i].ToString().ToUpper());
      else
      {
         if (field[i].ToString().ToLower() != field[i].ToString())
         {
            // The current char is in upper case format.

            if (i < (field.Length - 1))
            {
               // Move forward & backward on the string and see if the previous/next char is in lower case.
               // If so - put a space to separate the words.
               if (field[i + 1].ToString().ToLower() == field[i + 1].ToString() ||
                   field[i - 1].ToString().ToLower() == field[i - 1].ToString())
               {
                  formattedField.Append(" ");
               }
            }
         }

         formattedField.Append(field[i]);
      }
   }

   return formattedField.ToString();
}

Usage:

// Print: Total Mails
Console.WriteLine(FormatField("totalMails"));

// Print: User ID
Console.WriteLine(FormatField("UserID"));