Hey Arek, my bad I forgot one layer is a gdb. Is this the right code for joining 2 fields in a shapefile and 2 fields in a gdb??
import arcpy, traceback
from arcpy import env
mxd = arcpy.mapping.MapDocument("CURRENT")
# Join Fields
fc1 = 'K:\TASS\4_MAPPING_DATA_SUPPORT\Traffic_Mapping\Traffic_Count_Data\2011_Counts\2011_Annual_Stations\Annual_Stations_2011.shp'
fc2 = 'K:\TASS\4_MAPPING_DATA_SUPPORT\Traffic_Mapping\Traffic_Count_Data\District_Labels_Folder\Abilene_Labels.gdb'
fields_to_join = ['!F2011_TRAF!', '!FLAG!']
arcpy.AddField_management(fc1, 'COUNT', 'TEXT')
arcpy.CalculateField_management(fc1, 'COUNT', ''.join(fields_to_join), 'PYTHON')
fields_to_join = ['!TextString!', '!TFLAG!']
arcpy.AddField_management(fc2, 'TRAFFIC', 'TEXT')
arcpy.CalculateField-management(fc2, 'TRAFFIC', ''.join(fields_to_join), 'PYTHON')