Here's a short macro that will do this:

Sub AddComma()

Dim cell As Range
For Each cell In Selection
If cell.Value < "" Then
cell.Value = cell.Value & ","
Else: cell.Value = cell.Value
End If

Next cell

End Sub

Place the code in a general module.

Select the range of cells in question then run the macro.

Biff

"ChrishBiz" wrote in message
...
I have a list of about 23,000 emails. I need to make an E-mail blast. The
only way I know how to do that is by adding a comma at the end of each
one.
How can I save the hassle of inserting a comma manually into each cell?