MeeGo-powered Nokia N9 has a Facebook application made specifically for it.
Here are screenshots of the different sections of the app --
TP Quick Commentary:
1. FB for Nokia N9 has a drop-down main navigation menu that's easily accessible from all sections of the app. You can show or hide it with one swipe. I think it's ingenious. FB for iPhone and FB for Android both don't have this feature
2. I don't think anyone will have a problem using this application. The lay-out and interface are already familiar. Even the main navigation looks like that of Facebook for Android and Facebook for Every Phone.
3. What I love about this app is how sleek and refined the design is. It's just both easy to use and easy on the eyes. The default font is simply elegant and the color choices are subtle yet effective. Nokia also used the trademark squarecle shape in various elements of the application.
PS: Oh, and one more thing, Chat on FB for Nokia N9 is integrated with MeeGo's Messages Application. This means that you can save your FB Chat messages along with SMS and MMS you receive on your Nokia N9.