How to change Spark plug on fiat punto?

I want to find out how to change the spark plugs of a fiat punto on a 03 reg.

I had a problem when i tried to remove the spark plug leads which would not come off, they were shut tight.How to change Spark plug on fiat punto?
If it's a diesel the leads are threaded onto the glow plugs.

Sometimes the leads are hard to remove from a gasoline engine because heat causes them to bond to the plugs. If that's the case you can buy a tool that makes it easier to remove the leads.