A waitbar with ETA, Estimated Time of Arrival...
Fraction: is a number between 0 and 1. a value of 1 means completed and closes the window.
optional_arguments: are passed on to waitbar (see help on waitbar).
h: window handle.
some nice features:
* Estimates how much time before completion.
* Automatically open and close the waitbar window.
- It closes the window when fraction reaches 1
* it will chrash if you close the window (useful if you want to abort a running program)
* avoids updating the screen overly frequently.
Note: There are alternative (& more feature rich) progress bars on the fileexchange, but this I believe is the simplest to use.