Free Mobile Call Without SIM Card?
This video from Metacafe which shows you can make a phone call using your Nokia N95 even if it has no SIM card.
The application being showed here is called fring which you can download and install to your phone. The software is limited Nokia 3G or Wi-Fi Symbian handset.
My N6233 is not yet supported but if any of you guys have an N70, N80, N90, N6600 and E60 series phone, you could try this.