Does an iphone need a sim card if so where does it go?

You will be a great help i've just got this iphone 4s and me and mum are confused to where it goes and if it needs one? Because were confused to wether it needs a memory card and a sim so confused please help

Yes it does need a SIM card
This link may help you
http://support.apple.com/.../kb/ht5163

First of all, you need a pin. (or something as thin)
And you need a micro Sim.
I would've explained but I found a good video for you

Depends on which carrier you are on. If on a CDMA carrier (Sprint, Verizon) then you don't need a SIM as they don't use those. If on a GSM carrier (AT&T, T-Mobile) then you use a SIM which would go on the right side of the device.

No iPhone uses memory cards.