iPhone Help, Please!

[tsc12]

Hi, i have been searching forums for a couple of days now and i am still none the wiser. I live in the UK and i am looking to buy an iPhone and i am in a contract with Vodafone so i cant change. I have two questions;
1. Which phone would be a better choice to buy, the American version or UK, as i can easily get either. Which would you choose in my situation?
2. What is the difference between, jailbreaking, unlocking etc.

If anyone has advice on which phone to get i would be really greatful.
Thanks for your help.

 

[veeco3110]

1. get either one its the same thing

2.get either one its the same thing.

buy a uk phone with 1.1.2. on it and unlock it to use your current vodafone contract til it runs out and then get O2.