We just stumbled upon some old screenshots of the first versions of FretBoard. Back in the old days, FretBoard was programmed for the Palm PDAs and it was released as an open source application and is still available at the Sourceforge repository.
Here is a screenshot of the version 0.9:
And here you see the more advanced v1.2 which introduced the “Magical Note Bar” as can be found in the current iPhone version.

The most interesting thing is, that the old FretBoard version still runs on the current Palm devices as can be seen in the following picture. Thanks to Locks for the picture of running FretBoard on his Palm T|X.

