How to save all my data to the handset rather than the SIM?

I'm changing my O2 SIM card to a giffgaff SIM card and I was told to make sure to save all data and contacts to the phone so when I change SIM cards I don't lose anything. I have an iPhone 4. How do I do this?

I'd appreciate any tips or step by steps for things to consider when you're changing SIM cards in the same phone and keeping the same number.

Any help would be really useful!

How much can an iphone 4s 8gb hold?

Can it hold 500 pictures because i always take pictures and can it hold 50 songs and 50 contacts thanks for anyone who can help because i need to know if i have to get the 16gb but i don't think i have enough money for the 16gb so i need to know if the 8gb holds enough.

Can't get out of safe mode IPHONE 4

I plugged in my iphone so itunes would sync and i got a error message saying that it could not read the iphone and it told me to reset all setting so i did, then when i restored from back up, I was on safe mode and i tryed restarting springboard but its still on safe mode so i deleted winterboard and still nothing. My iphone 4 is 5.1.1, Please help me! I don't want to reset all data

How to upload cover photo on Facebook app for iPhone?

There was a new update yesterday, August 23rd, and it happened to change the option to upload a cover photo via Facebook app. Now it won't show the option! I want to upload a picture from my camera roll on my iPhone. Can I still do that? If so, please explain thoroughly, please and thank you.

How to get music off of a laptop onto my Iphone 4?

I had recently gotten a new laptop and new music on itunes, and it's not letting me drag and drop any music onto my phone. I've tried looking for solutions but the only one I've found is to manage music manually, but there's a pop up box that say's that if I continue it'll erase everything off my phone. Is there a way to drag and drop music without syncing or deleting any of the things on my phone now?

How to upload a cover photo via Facebook iPhone app?

I had seen the option before, but now when I go to my timeline, it won't show the "add photo" link to add a cover photo. I had just updated it yesterday (August 23, 2012) and I think the update changed it. Does anyone know how I can or if I still can upload a photo VIA MOBILE APP? I do not have access to a desktop, so that's why I'm trying to figure it on my phone. Btw, I have the iPhone 4.

I need an iphone app to make and receive calls?

I need an iphone app that will give me a number and anyone can call that number and i'll receive the call on my iphone i don't like google voice i need the app to have it's own number in my same area code when someone calls that number it will make my phone ring thats how i want the app to work i don't just want an app that lets u make outgoing calls please include names of apps so it's easier to find in the app store thanks