How to download you tube videos on my IPhone?

Is there a particular app that I can get from the app store which downloads videos from youtube…
Thanks in advance…

Added (1). Thank you both for your aswers… Ashok are you using tubemate on your Iphone? Coz I can't find an Iphone version (for OS 6.1.3) on their website or Itunes…

How to backup my apps on my iphone 4s before downgrading?

I'm looking to downgrade iOS 6.1.3 to iOS 6.1.2 on my iphone 4s by downloading the 6.1.2 ipsw file, so I can jailbreak. However I don't want to lose any of my apps or app data. I want to know: 1) Is that kind of downgrading even possible? 2) How can you backup your apps and app data, and restore them when you're done without going back to 6.1.3?

Best thing to clean iPhone screen with?

My iPhone 5 screen is really messy, I had a screen protector and regret taking it off, does anyone know of anything that I'm likely to have at home to clean it?

What Can I Get From Vodafone UK?

My contract from Vodafone end within the next two weeks. I'm after a new phone and I really don't know what I can squeeze out of them.

I've been told that if I speak to my Vodafone shop and am not satisfied with the offer I should ask for my PAC code and wait until another salesperson contacts me. I've been told that these guys are from Vodafones Retention Department and that they have the ability to offer very good deals. So what can I hope to squeeze out of them.

I've just finished a two year contract. My bill was in the region of £25 plus per month.

Let's say I was looking the iPhone 5 32GB, unlimited calls, unlimited texts and 4 GB. Vodafone's website advertise it at £52 month with the handset costing £19. With a bit of haggling with Retentions what could I get that for £25 - £30 month with a free handset. Or is that been to optimistic?

Or say I was to go for the Samsung Galaxy S4 again the site advertises it at 24 months, Unltd minutes, Unltd texts, 1 GB mobile internet data for £37 month again would I be asking to much if I were to look it at say £20 month.

I've heard somewhere that with all the bits and pieces that Samsung has added to the Galaxy that the standard 16GB that comes with the phone may prove insufficient.Am I correct and what should I look for if I were to be offered one at £20 month. Would I be pushing the boat out to far if I were to ask for 2GB data.

I know these may seem ridiculous prices but from what I'm reading Vodafone retention have a very big scope when dealing with retentions. Then again maybe I'm been like Vodafone to greedy. I'm also just trying to get an idea of what it is realistic to ask for.

How to disable WAP or Mobile Internet on iPhone 4?

My iPhone 4 keeps using my mobile internet even when I don't want it to and it's using up my credit. I have connected to my Wi-Fi and I think that it is using that connection to browse the internet. However, I keep getting notifications saying something along the lines of: ''You can't access anymore data via WAP please top up credit. I know my phone must be somehow using WAP or Modbile internet because all my credit has gone.

How to get the new iPhone 5S for cheap price?

We all know there's going to be a new iPhone 5s. China even spill the beans and leak some details about the new iPhone. My question is how can I get it at a cheap price? When the iPhone 5 came out I believe for Black Friday it was 183 dollars for straight talk. Or was that the Christmas deal? Anyways I was wondering if they might do the same with the iPhone 5S? Do you think so?

Does the iPhone use Wi-Fi for everything or just for data?

When you have your iPhone connected to your wireless network at home does it use that connection for everything like voice calls, Internet, and text messaging or does it maintain a simultaneous link to the cellular network for things like voice calls and text messaging?