Mac os X Notifications

Hi,

I am in an open-source game community and we are trying to find a way to get notifications on Mac. I thought of having either the notifications on 10.5 like this:

or the Mac os X Lion notifications.

Are the 10.5 notifications working on Lion?

We will probably use Lion Notifications. But how do we implement some Lion notifications in our code?

Thanks,

Fordcars