yes thats what I meant, the thing on the bottom of the phone doesn't count as a headphone jack because its not. But yes, they are compatible.

The N70 is a smart phone, K750 is not so theres alot more features in the bigger case. Screen looks bigger too plus as it has 2 cameras I assume it'll do video calling?

Re the sim cards: watch the hotmail adverts, they quite often come up on there  Max of 6 per customer.