I've never used IBM Cognos product. What I need is to make an integration between a custom system and Cognos. I don't know yet the requirements but I have one question:
Does Cognos have REST/SOAP web services one can connect to and retrieve data? Or maybe an SDK? How do you guys integrate with Cognos?
You'll need to use Cognos mashup services which is part of Cognos SDK:
http://www-03.ibm.com/software/products/en/cognos-mashup-service
The documentation of this product is not available in public URL and it is available only as part of the Cognos SDK installation.
However you get a hunch on it in here:
Get started with the IBM Cognos Mashup Service
and in here:
Combining IBM Cognos Mashup Services and Google Maps v2