This is a simple program that will easily allow you to control the pins on your parallel port directly. Manual toggle is available, as well as a simple language that allows for sequencing.
The initial intent of this software to allow control of various external devices, such as LEDs (or other indicators), or anything that can be controlled from a relay. The first full application will be sequencing a series of solenoid control valves for a water fountain.
I've used Glade for the GUI design, written the code in C, and the backend syntax and grammar parser in flex and yacc/bison, respectively. Everything is integrated through the GNU autoconf and automake tools, and I used Anjuta to put it all together and keep things sane. Great tool.
Download version 0.1 here.
Be warned, it's not very functional yet, but can do basic sequencing and manually drive the pins.