A database of all vendors, contracts, and payments that have been posted by the municipal government of the City of Chicago to the Vendor, Contract, and Payment Search lookup tool maintained by the Department of Procurement Services.
This is by no means a complete list of entities making money from the City. It's just a useful way to see information that is already published, and used extensively by journalists, but not readily available to the public.
More about the source can be found here: http://www.citypayments.org/source/
Good web interface but no bulk download or API available as far as one can tell.
No license statement re data though footer states "Please use this data for good." Data is itself scraped from City of Chicago website.
|Autore||Daniel X. O'Neill|
Vendors, Contracts and Payments for the Muncipal Government of City of Chicago. Daniel X. O'Neill.
Retrieved 20:57, Jun 19, 2013 (UTC).
the Data Hub