How do I update my iPad 2 to IOS 5? & another little question.

Okay so, I've had my iPad 2 for a while now and I have never had to update it. It hasn't given me an option to yet this whole time, and I want to update it. Help!?

My other question was about my iPhone 4s. Ive had it since like april or may, and I have no problems up until now, i rented a movie yesterday and the persons house I was at didn't have the best wifi, so it wouldn't download,I thought okay I will just watch it when I get home tomorrow morning, because I have good wifi. Anyway it won't down load or even try to download.