Some sort of free REST API would be ideal, but in general is there any free API or web service or CSV file (that's not behind a password prompt) or anything out there that one can query to get the current list of the S&P 500 index constituents?
I've looked on S&P's site itself (http://www.standardandpoors.com), through Yahoo Finance's API, and Markit on demand (http://dev.markitondemand.com/), but have not been able to find anything yet.
I found http://finviz.com/export.ashx?v=152&f=idx_sp500&ft=1&ta=1&p=d&r=1&c=1
:-)
But I haven't found Finviz API documentation.
:-(
Bloomberg seems to have an open api. Might find the data you need if you dig around.