Hi -
The software is contained within the Software Center --> Lan Switching Software --> Catalyst 6000 --> Download Module Software -->
Download Firewall Services Module(FWSM) Cryptographic Software.
Here's the direct link, assuming you have a valid Smartnet contract which would permit you to access this link:
http://www.cisco.com/cgi-bin/tablebuild.pl/cat6000-fwsm
The latest software is 2.3.2, which was released yesterday.
Let us know how else we can help.
thanks
peter