Is unlocking an iPhone illegal?

My family and I are currently using At&t, but the data plans are getting expensive. We have 3 iPhones and all of our contracts would end in one year. We're planning to switch service providers after the contract end, but we still want to use our iPhones. Is it illegal to unlock the iPhones after the contract ends in order to use them at another cheaper service provider?

Thank you

Added (1). I was looking at T-mobile. On the Apple website, you could buy a factory unlocked iPhone for way more because T-mobile doesn't have a contract. It sucks. My bill at at&t has reached 240 a month. The consumers always lose.

Having problems watching Instagram videos?

I have an iPhone 4 and I've updated the app. I was able to watch 1 video and now when I select play it doesn't play at all but then a replay symbol shows up. Anybody else having this problem or have a solution?

What is Imessage on Iphone 3GS?

My friend says I can text her for free on using Imessage which is cool and all, how does that work though?

Added (1). @ Kailee Iphone 3GS's do have imessage, I'm using it right now

Why do some songs stop playing and won't load on Spotify?

I found this on a question posted two years ago - I'm having the same exact problem. The best chosen answer was to kill the app and then re-open it. This does not work. I'm getting really upset because I pay $10/month and half of the songs on my playlist stop playing. Help! I'm hoping that since 2011, there have been advances in knowledge as to why this happens! Anything helps. Thanks!

Previous Question:
I just got Spotify and signed up for the $10/month plan that includes the mobile access. I'm somewhat disappointed, however, because the app has a terrible layout that makes it incredibly difficult to find music that you've saved (all you can do is add it to a playlist or create one). But what is most disappointing is that random songs will not play on the mobile app (iPhone at least) but they will play on the computer program. The songs will not be grayed out as unavailable and will appear to be completely accessible, but when you press to play one of these random songs, it will bring up the album picture and look like it's going to play, but never loads the song.

Samsung Galaxy S4 Active or IPhone 5?

I'm scared to make the change from iPhone to The Galaxy. I've used iPhones for at least 3 or 4 years now and I'm just nervous I won't like the galaxy? Lol i don't know. What's your opinions?

What are iPhone 5 must have accessories?

My boyfriend is buying me an iPhone 5 for my birthday and I want to get all the things I need before I get it. I have purchased some cases and I don't want screen protectors as I had one for my iPad and I hated it! But apart from that if anyone haas any ideas on what else I need please let me know.

How to transfer an iPhone 4 SIM Card?

So I just got my second iPhone 4 for free because of a sleep/wake button defect, Verizon sent me a brand new iPhone 4 in the mail. It came with an instruction sheet that is telling me to remove the phone's SIM card in order to transfer all my contacts and all that. I looked up some Youtube videos on how to remove it but they were all iPhone 4s' and they had the little dot on the side to remove it with a paperclip. My iPhone 4 has nothing on any sides, just the buttons, the headphones slot, and the mic. The mic hole kind of looks like the hole for the paperclip but I don't see any slots for the card to even come out.

Wouldn't turning off iPhone while charging shorten battery life?

They say the iPhone has a battery life of 400 full charge cycles before it starts its decline. Ok here is the thing… A lot of talk on how to save battery life on the iPhone by charging habits such as turning the phone off while charging, airplane mode while charging, turn off Wi-Fi bluetooth etc… But if the phone charges faster… Wouldn't that increase the amount of full charge/discharge cycles and there for decreasing the life of the battery?