Skype on the iPhone

I'm not that big on talking on the phone so I've never bothered with Skype.

So many people I know rave about it but I hardly ever call people.

Anyway yesterday I heard that Skype was available for the iPhone.

I saw several tweets about it. So I downloaded it.

But what now?

A regular Skype user would probably know what to do with it but I'm a little unsure.

If I make local landline calls what do they cost and how do I pay for them?

Anyone?