import arcpy, arcgisscripting
gp = arcgisscripting.create()
mxd = arcpy.mapping.MapDocument('CURRENT')
df = arcpy.mapping.ListDataFrames(mxd, "Layers") [0]
Parcel = gp.GetParameterAsText(0)
whereClause = "GEOCODE ='%s'" % Parcel
arcpy.SelectLayerByAttribute_management ("Parcels", "NEW_SELECTION", whereClause)
showMessage("Parcel not found. Please try again.")
df.zoomToSelectedFeatures()
arcpy.RefreshActiveView()