Yes, an event will pop up named with the month and the year of the collected photos from photostream. So for example if you take pictures this month, you should find an event in iPhoto called "August 2012 Photostream". Every photo taken on a photostream enabled device in the month of August will be automatically imported into iPhoto and put into that event I just mentioned above.
However I myself am a bit confused with how photostream actually works on a Mac. If you notice on the hierarchy tree on the left, you'll see Photostream as well. Not sure if these are just duplicates of the already imported photos from photostream, or if these are not actually stored locally on your hard drive.