I heard about Cathode (by Secret Geometry) while listening to the Mac Break Weekly podcast. You will have to decide if the nastalgia of days gone by is worth $9.99 (in apple app store) to you. However, having actually used terminals "back in the day" that looked like this and wanting to support developers who are not just geeks, but creative geeks... I have already purchased my copy.
How could I not buy it when this is the extent of their about page.
Secret Geometry, Inc. is a small studio in the Pacific Northwest. We make apps and collaborate on art installations.
Just a quick note (according to their site), you can use it for free with the following caveats. (again... love supporting creative geeks with my hard earned cash... so I bought it ;-)
Cathode is free to use, but the picture will slowly degrade unless you purchase. Effects like static and flicker will increase over time until you relaunch the app.