String Interleaving

//Related to Question at:
//http://groups.google.com/group/dotnetdevelopment/browse_thread/thread/94c1efd1c6a26e3c

class Program
{
  static void Main(string[] args)
  {
    // The Parse method parses a given string. This was only for testing. I then used the same logic for the ParseFile() method.
    //List<string> strings = Parse(args[0]);

    List<string> listA = ParseFile(@"C:\strings.txt");
    List<string> listB = ParseFile(@"C:\strings2.txt");

    List<string> listC = Interpolate(listA, listB).ToList();

    //TODO: Output listC to a third file. No big deal here.
  }

  private static IEnumerable<string> Interpolate(List<string> listA, List<string> listB)
  {
    //List<string> list = listA.Count < listB.Count ? listA : listB;
    // An iterator block is overkill, here. Used for convenience only.
    for (int i = 0; i < listA.Count; i++)
    {
      yield return listA[i];
      yield return listB[i];
    }
  }

  private static List<string> Parse(string p)
  {
    List<string> list = new List<string>();
    int stringLen = p.Length;
    if (stringLen > 0)
    {
      char c = p[0];
      StringBuilder sb = new StringBuilder(c.ToString());
      for (int i = 1; i < stringLen; i++)
      {
        char nextC = p[i];
        if (char.Equals(c, nextC))
        {
          sb.Append(nextC);
          continue;
        }
        list.Add(sb.ToString());
        sb = new StringBuilder(nextC.ToString());
        c = nextC;
      }

      list.Add(sb.ToString());
    }
    return list;
  }

  private static List<string> ParseFile(string fName)
  {
    using (FileStream fs = new FileStream(fName, FileMode.Open, FileAccess.Read, FileShare.None))
    {
      using (StreamReader sr = new StreamReader(fs))
      {
        List<string> list = new List<string>();
        int i = sr.Read();
        if (i > -1)
        {
          char c = (char)i;
          StringBuilder sb = new StringBuilder(c.ToString());
          while ((i = sr.Read()) > 0)
          {
            char nextC = (char)i;
            if (char.Equals(c, nextC))
            {
              sb.Append(nextC);
              continue;
            }

            list.Add(sb.ToString());
            sb = new StringBuilder(nextC.ToString());
            c = nextC;
          }

          list.Add(sb.ToString());
        }
        return list;
      }
    }
  }


}