Gestate is a freeware obstetric calculator designed to replace the cardboard "wheel of fortune".  It allows for a variable cycle length and also returns the day of the week of the EDD.  Other than this however it is as inaccurate as its low tech counterpart!
Installation
This small application takes less than 1.5K of disc space.
Gestate.opa should be copied to any  \app directory and installed in the usual way using the <Psion+I> command. 
Instructions
Enter the LMP or use the standard Psion shortcut keys such as <TAB> to display a calender.
Enter the cycle length (limited to 20-40 days)
or alternatively enter the known gestational age.
The EDD is then calculated.

If you like the program or have any suggestions please e-mail me (101660.1310@compuserve.com)
Disclaimer
This program is no more accurate than analogue tables and only gives a guide to the expected date of delivery. This unsupported freeware has been extensively tested and no bugs have been found however no liability can be accepted for its functionality  or for any damage done to your machine.

Dr PJ Buxton FRCR