Hi there
Are you looking for current or historic stuff?
US only or European/Worldwide?
If you're looking for current data then the question will then be: how current? The newer the data, the more likely it will cost you money and there will be stringent restrictions on what you can do with it.
For example, my previous clients in London had a live link to Reuters on a Triarch system. By massaging the data slightly with a wider spread, we were able to re-publish it back to them and disseminate it via web pages. However there was no way they would allow us to provide a feed service to web clients of ours of the raw data. You can see this in action at
www.finspreads.com - the data you see now has been re-written, but the data manipulation is still my SQL trading system.
HTH,
Simon