how to interface arduino uno with atmega 328 and hall effect sensor ,gsm module

i going do a project on transmission line controlling and monitoring using gsm module in arduino platform so pls help mee

What have you tried?

You could use SoftwareSerial on both devices. Have a look at Serial Input Basics. It can easily be adapted for SoftwareSerial.

How far apart are the two devices?

How many bytes per second do you want to transmit from the 328 to the Uno?

Do you really need two devices in the first place?