I have an iPhone 3GS I no longer use as the battery does not hold and I have a new iPhone 4. I was thinking of using it from time to time at home just to browse or read emails without cellular network (i.e., with no SIM).

After a long time I switched it on initialized it and realized that I need a SIM to activate it (although I already activated it years ago).

What are my options? Can I activate the old 3GS with my current SIM or will I *deactivate* my new phone? Should I try to get a *Phonebook* SIM? I would prefer not to jailbreak it if there is a way.