How to navigate in 3d space in V2.5

I switched to version 2.5 today and i am having a little problem navigating in 3d space in this version, it is a little bit different than the old version.
In blender 2.49 I used to click the “alt” key and left click to navigate the 3d space to view my model from a free angel but it is not working with v2.5
Anyone can tell me please the proper shortcut? ( On mac computers with no mouse )

From the User Preference / Input select Emulate 3 button Mouse

Ah, there it is thanks.