Code:
Public Sub List_Load(TheList As Listbox, FileName As String)
On Error Resume Next
Dim TheContents As String
Dim fFile As Integer
fFile = FreeFile
 Open FileName For Input As fFile
   Do
     Line Input #fFile, TheContents$
        TheList.Additem TheContents$
   Loop Until EOF(fFile)
 Close fFile
End Sub

'Usage:

Call List_Load(List1, "C:\MyFile.txt")