All of the FlexNET modules, save 1, are available via FTP and on various web sites.   You can set up an operational FlexNET user station with all sorts of different I/O with the available code.  In order to set up a node/digi you need to get the flexnet.exe file.  This is available for free for the asking.  To ask, send an email to:
<flexnet@afthd.tu-darmstadt.de>
stating that you would like to receive the node module. The mail should contain at
least:

your amateur radio callsign
your digipeaters' callsign
your email address for reply mail
the IARU locator of your digipeater
the city/state of your digipeaters location.

This is mainly to help us keeping track of how many people actually use a FlexNet
node.