Installing more RAM on a mac?

I have an Imac that I bought about a year ago an only have 1GB of ram. Id like to upgrade to 4GB. It seems like a pretty easy thing to do, just pop off three screw remove the old ram and plug in the new then start the computer back up. Is it really this easy? I would rather not pay someone to do it if thats really all there is to it. Is this something best left for experts?