If you're looking to invest in ETF's, I found a great worksheet that breaks them down. It was put together by the Bespoke Investment Group. You can view it by clicking here.
Right now I'm intrigued by ETF's to track various industries. With the market getting into a somewhat overbought position, there are funds that allow you go short on the market, which could be valuable in the next six months.
I should mention that I found it displayed on James Altucher's daily blog watch at thestreet.com, which is a nice resource.