Data Acquisition Omni CD is free to download (113.5MB): http://www.datx.com/products_software/dataAcqOmniCD.htm
Then there's the LabVIEW library, DT-LV Link, for $195: http://www.datx.com/datx/products_pricing/prod_DT-LV_Link.jsp
You didn't mention your OS but if it's Linux there's always the Comedi project. It supports a large amount of old hardware: http://www.comedi.org/hardware.php
Use that in combination with the Comedi Library for Linux on OpenG: http://openg.org/tiki/tiki-index.php?page=Comedi+Library+for+Linux
