Question : Problem: need to setup 2 SSiD's that cannot talk to each other.

I'm currently working on a wireless solution for our corporate environment. We need to have the ability to segregate a "guest" wireless access connection from the "corporate" user wireless connection. This way guests or consultants can use the "guest" wireless connection to get to the internet only and not our corporate resources.
I currently have the AP configured and working with one SSID and WPA encryption.

Answer : Problem: need to setup 2 SSiD's that cannot talk to each other.

I have read over this article and found some useful information.  I also have a client with a Cisco Arionet 1130 and have looked through some settings.
http://www.cisco.com/en/US/products/ps6366/products_qanda_item09186a00809ba482.shtml

It looks like you can create a new SSID and assign it to Guest Mode.  In order to configure different encryption types for multiple SSID's you must configure them in the "Security->SSID Manager" page, not under "Express Setup"

Another option would be to setup VLANs and assign the Public SSID to a different VLAN than the Private SSID.

From the reading, it looks as if assigning one SSID to Guest-Mode will solve your problem.  I would highly recommending TESTING this before throwing it into production.