Sub Macro1()
Dim MyPrefix, CellLink As String
MyPrefix = "http://www.diddly.wotsit/"
Do
CellLink = MyPrefix & ActiveCell.Text
ActiveSheet.Hyperlinks.Add Anchor:=Selection, Address:= _
CellLink, TextToDisplay:=ActiveCell.Text
ActiveCell.Offset(1, 0).Select
Loop Until ActiveCell.Text = ""
End Sub
Select the cell at the top of the column and this will run downwards until it encounters an empty cell.