Ever since the iPhone App Store launch last month, we’ve been on the hunt for apps we can load on our fancy phones and not forget about immediately. Occasionally something pops up but, sure enough, we manage to forget about it in a matter of days. But here … this is different. Frotz we’ll keep around for a long time. Some of you may be familiar with Frotz; it’s a Z-machine, used to read and, therefore, play interactive fiction.