Where can I find licensing information and pro/standard version differences?

I'm very new to Unity and trying to assess whether I can use it to develop casual games.

Can anyone tell me where I can find information about the free version license? I specifically need to know if the free license expires after 30 days as it says on the registration page. Also can it be used to develop commercial games?

Is there a table somewhere that shows the differences between the free version and the pro version.

http://unity3d.com/unity/licenses