Use an article database such as ABI/Inform to look for articles about exchange traded funds (ETFs); you may also want to look for articles comparing them to index mutual funds.
For information about a specific fund, use S&P's NetAdvantage. Look for the "Mutual Funds/ETFs" tab at the top, then use navigation options along the left side to find more information.
You may also want to check out Morningstar's ETF Center, which includes a fund screener. Yahoo! Finance also has an ETF Center that is a good source of information about particular funds, as well as educational articles about how ETFs work.