How to switch over my iPhone activation?

I have the iPhone 3Gs and my friend recently gave me her old 4 when she upgraded. I'm not sure how to switch over my plan to the other phone because of the difference in sim card sizes. I have the sim card I need, can anyone help?

Added (1). ** I do have the sim card for the 4. **

You can tell your phone company, i presume AT&T since you had the 3gs, that you need a mini-sim and they should give it to you, it may cost between 20-70 dollars depending on how many times you've asked for a new one. If they ask you why you can tell them that you're switching to the iPhone 4, and they'll change it for you on your account. (this doesn't constitute an upgrade if that what you feared)

Just go to any local cellphone repair shop, they will cut your SIM with SIM cutter! Or order one from ebay: http://www.ebay.ca/...0370822675

  • Why is my iPhone copying the same video over and over? So I took a screen recording earlier today and when I went to send it, there were about 50 of the same video. I thought alright i'll just delete them. So I did. And they returned. I now have over 300 of the same video and it keeps copying itself.
  • Why does Netflix keep pausing and playing over and over? I'm using it on my iphone 4. And I have checked my connections over and over I've uninstalled reinstalled, signed in signed back and everything else that the troubleshoot website has recommend. And it's gotten annoying. It didn't start doing this as much until I updated the app before the ios 7 release. I'm currently using the trial for netflix and my laptop doesn't work so I can get it on anything but my phone.
  • Should I stick with iPhone or switch over to android? I'm thinking of getting a new phone and all my friends are telling me to get android but I don't know what to get
  • My iphone rebooting over and over? My iphne has been reboting itself. Its on for a few minutes but it just boots it self again. I tried every method but non of them work. I need the method for iphone 3g ios 6