LonelyPlanet's guide to Chile is a good general overview with some nice pictures. General information and links for health and currency are useful.
The American Chamber of Commerce (locally referred to as AMCHAM) has information about Chile and business, in English.
The U.S. Embassy in Chile has a comprehensive web site with country information and current affairs.
The U.S. State Department's Bureau of Consular Affairs provides Consular Information Sheets for a number of countries. You may find the general information at their Chile site useful.
The Embassy of Chile in Norway has put together a fairly extensive site which provides a wide range of information about Chile. This site includes lots of additional links - you might find the on-line newspaper links an interesting way to learn more.
ChipNews is a website with good current news coverage, extending beyond general news to include business news as well.
The Caliterra Winery has an interesting site that provides information on Chile and its wine growing regions. Their site includes authentic Chilean recipes if you want to get a "taste" of Chile before the trip!
If you are looking for a site with search engines and loads of links tailored to Chile, check out Anancyweb. Be sure you scroll down to the English version of the AAA Matilda Chile search engine.
It's hard to argue with the kids at Yahoo ...their city sites are consistently exceptional. Visit their "front page to Santiago" to just about all you would ever want to know about the city.
Here's a website with information about restaurants, theaters, etc. It's in Spanish! But it's also somewhat easy to figure out restaurants, etc., and the addresses are provided. Take a look, even if you don't read Spanish, it might still make some sense to you.