Will I need to download anything else to jailbreak,unlock and activate my iphone 3g?

I am using ziphoneGUI V3.0 and my Iphone was bought in the US and I want it to work in India with any indian GSM SIM cards.And also i wanted to ask that is it safe to use the above mentioned software?And if not please suggest an easy tro use and free softeare with a small size.P.S>It should be very easy to use.My iphone is the latest version costing $99.