Spanish Contract Mobile - Best Deal??

Hi, hope someone can help.

I am looking to get a phone on contract, if possible an iphone or a blackberry.

I've been looking at Yoigo and Movistar, however the contracts that they are offering look really confusing to understand. Can anyone please explain to me in simple terms how it works over here?

i.e, on average how much would i pay per month
Is it common to get free texts and calls in a tariff?

Are there any networks or tariffs which offer free internet minutes or cheap internet browsing via the mobile?

Any info would be greatly appreciated.

Many thanks