How to add new button to my custom bar?

Hello, I want to add a new button to my fckeditor bar, like livejournal "embed media" to embed some google videos or youtube videos and so one, I was trying to find out here if anybody except me had such need, but nothing.

So I need an advice how can I add a new button and my functionality with existing fckeditor api.

Thank you.

P.S. sorry for my poor english, it's not my mother tongue.