How can I insert any sim into my iphone?

[Sycamoira]

It's called "unlocking the iphone" and sites and videos to assist you are all over the internet.

 

[Matthew D]

I already jailbroke and have cydia. I also only have a mac!

 

[kerslake]

you can unlock it via the internet, or go to a shop, most high-street phone shops should do it