You both can download the Finance Act 2009 from here http://www.caclubindia.com/share_files/finance-act-2009-24950.asp
In that file see page no. 41 of the act. It clearly states 2. In the case of a company— (a) where the company is a domestic company— (i) on income by way of interest other than “Interest on securities” 10 per cent.;
Refer this discussion for rate before 01.10.2009 http://www.caclubindia.com/forum/tds-rate-for-company-deductee-for-period-april-09-sep-09-76753.asp?1=1&offset=2
) now 
