Investors looking to buy exchange-traded funds face a tsunami of choices these days. With just over 1,000 ETFs traded in the United States, it can be a challenge to differentiate among them and determine which best fit your goals. The decision calls for careful research, but for newbies, finding a good go-to source can be difficult. "It's important to realize that ETFs are a different animal [than mutual funds], and it's harder to get the data," says Dave Nadig, director of research for IndexUniverse.com. One issue is the profusion of ETFs covering just about every nook and cranny of the market, many focusing on the same asset class, country, or industry. How do you choose between the Vanguard Emerging Markets ETF and the SPDR S&P Emerging Markets ETF, for example? Sure, you can get information directly from the individual providers, but a handful of websites can help you wade through the vast amount of data and also compare funds. Here are three such sites:

dblclick('xxlA');

[Also see U.S. News's list of The 100 Best Mutual Funds for the Long Term, and use our Mutual Fund Score to find the best investments for you.]

1. ETF Channel (www.etfchannel.com). Launched in June, this site targets both retail investors and investment professionals. One of its basic features allows users to enter an ETF symbol to find out what stocks or other securities the fund holds. Alternately, investors can type in a stock ticker to see which ETFs hold that particular stock. So if an investor is interested in a handful of companies but doesn't want to buy each stock individually, this tool can potentially locate an ETF that holds a basket of them.

Looking for, say, a faith-based fund or one that invests in Russia? The site's ETF Finder will produce a list of ETFs that focus on a particular industry, country, or segment of the market. Users can also review top-ranked ETFs, calculated by the weighted average broker recommendation of their underlying stock holdings, and view "unloved ETFs," those with the smallest dollar amounts traded within the past 30 days. This feature is "interesting more than anything," says site founder Adam Menzel. "In the past when ETFs have very little volume and are not traded very much, they sometimes get de-listed ... not to say they're going to be de-listed, but it's something to keep an eye on." The site's tools and features are free, but users must register.

[Follow these 5 Steps to Set Up an ETF Portfolio.]

2. IndexUniverse (www.indexuniverse.com). Known for its comprehensive coverage of the ETF world, IndexUniverse also offers a range of tools for new and experienced investors. For the novice, an education section explains the basics—how ETFs work, where they fit into a portfolio, and how to evaluate and trade them. If you're ready to dig in, a quick search on the site allows you to compare ETFs within a particular asset class. A search for a broad market fund, for example, turns up 20 offerings from providers that include Schwab, Vanguard, and iShares. You can then sort by specifics such as expenses, return, and standard deviation (a measure of volatility). Once you've whittled the list down, you can view each fund's holdings, assets, and country and sector breakdowns. Searches can be saved. The site also overs a wide range of ETF news and commentary.

3. Morningstar (www.morningstar.com). It's best known for mutual funds, but Morningstar has expanded its coverage to include ETFs in recent years. Aside from stories and a broad collection of education-related articles, the site offers a screener that can filter funds by basic fundamentals, such as performance, as well as metrics like valuation, liquidity, portfolio style, and index correlation. Users can click on specific funds to find more detailed information on performance, holdings, and risk, as well as brief snippets of analyst reports. The site also offers pre-sorted screens on the most heavily traded ETFs, top performers, and lowest price to fair value ratio. "Premium" members who pay a subscription fee can gain access to the entire site, which includes full analyst reports on certain mutual funds and ETFs.