Well if you want do it with WM_KEYDOWN then the keycodes are the same as the Ascii values, but it'll all be in the same case:

VB Code:
  1. Dim sText As String, N As Long
  2.  
  3. sText = "something"
  4.  
  5. For N = 1 to Len(sText)
  6.     PostMessage hWnd1, WM_KEYDOWN, Asc(Mid$(sText, N, 1)), 0
  7.     PostMessage hWnd1, WM_KEYUP, Asc(Mid$(sText, N, 1)), 0
  8. Next N
Perhaps try WM_CHAR