Iphone 4/4s with Straight Talk?

I'm really confused with this and I would like to know!
I've been reading about Straight Talk and their $45 Unlimited monthly plan. I've also read about how you can now use AT&T based phones and T-mobile phones.

My question is, if I buy an Iphone 4/4s from AT&T, can I use it with a Micro SD sim from Straight Talk? If so, how do I activate it? Can I just activate it like I would any other Iphone?

I would also like to know how exactly it would work, if it does. (The plan that is, with the phone.)

ANY information on ST would be very helpful, especially with the use of Iphones.
(Does it get good coverage? How does the internet/data plan work? Can I still send MMS? Will I be able to use all the features just as I would with a normal Iphone plan?)

Sorry it's a lot, but I just want to be positive on this! Thank you. Any help is very much appreciated!

Added (1). Also, one more question: If MMS doesn't work until you get iMessage or whatever, can you still like upload pictures via facebook or the internet?

What happens to my phone plan when using an unlocked iphone?

I currently have a unlimited talk/text plan with at&t, I really want an iPhone 4, but my dad doesn't want to upgrade my plan to iPhone, if I were to buy an unlocked iPhone 4, and just put my sim inside, would this change anything on my plan? What I thought is, my plan won't change, I just won't have internet access unless I'm at home on the Wi-Fi internet. But all other features such as talk and text won't change, am I right?

How to use Wi-Fi only on my iPone 4S?

I'm travelling our of my country and i want to bring my iPhone for music and Wi-Fi access.
I don't want to get charged for roaming by recieving calls/texts/data.
How can i do that? How do i set my phone to be able to use Wi-Fi and not cellular stuff?
Also, would i still be able to use iMessage without being charged?

Why is my iPhone Wi-Fi acting up?

Okay so lately my Wi-Fi on my phone has been really annoying. Like I refresh a page or app and it like does the circle thing for a while and says error on the app. Itll be "refreshing" for a couple minutes and stop and its really annoying. But my Wi-Fi is fine on my computer and everything else. Please and thanks!

Iphone 5 and Dodge Uconnect System?

Purchased the Iphone 5. Have a 2012 dodge journey 4.3 inch display. Outgoing calls are fine. The issue is when i receive an incoming call and i answer through the buttons on the steering wheel the call will go directly to the headset on the iphone. So i'm stuck saying hello and the voice is not coming through the bluetooth in the car. I then have to transfer the call to the bluetooth. When i had the 4s, there was no problems. Just seeing if anyone is having the same issue. Contacted dealership to see if there's a firmware upgrade for the software or if maybe there's something in settings to get around this issue.

Does deleting an apple ID account on one device delete it on all others?

Basically I had an IPhone 4, but I've now upgraded to an iPhone 5. I'm giving my sister the iPhone 4 for her birthday.
Currently both devices have the same Apple ID and same iCloud account etc. I want to delete the apple ID on the iPhone 4, so that my sister can change it to hers, so that when she buys things, it doesn't come out my bank account! Lol.
I just want to know that if I click on 'delete account' in settings>iCloud it won't delete it off the iPhone 5 too, and I will lose everything including everything in iCloud.
I don't want to delete the account, just delete it off the iPhone 4.
What do I need to do? Thanks

Added (1). Oh, I don't know how to just log out on the iPhone 4, it won't let me? Okay then though, thanks