Calculate Distance Using Fields In Form?

However Instead of entering the postal code continually or selecting from the combo box. How do I set zipcode 1 and zipcode 2 based on fields in a form. I would like to use the current FROM (Default zip based on the current job in form) and TO zipcode [Project Postal Code] that is on the form at that time. Not necessarily combo box.

Currently you have

zip1 = Me.Combo2.Value
zip2 = Me.Combo4.Value

I want Zip 1 to be Default zip (however I can still change it if needed) ZipCode field is [Project Postal Code]

Here is the full code:

Private Sub Command6_Click()
Dim zip1 As String, zip2 As String
Dim sResponse As String
Dim sLink As String
On Error GoTo Command6_Click_Error
zip1 = Me.Combo2.Value

[code]....