financial databases

I wonder if anyone could help me in getting the historical database for several financial instruments such as daily t-bill rates together with daily derivative quotes over different exchanges and countries. There seems to be a problem in aquiring them for free. I am talking of moderatly sophisticated databases with many instruments with a big time span. Anyone knows the data sources i can get them for free?

The central bank websites of each country have alot of that information for free.

Be forewarned: You will spend hours searching for what you want, collating it, etc.

Here is a link to the banks:

www.bis.org/cbanks.htm

Regards.