As Google indexes Web pages, it retains a snapshot of the page contents, known as a cached page. When a cached page is available, you'll see a Cached link at the bottom of the search result.
Clicking on the Cached link will show you the page as it was last indexed on Google, but with your search keywords highlighted. This is extremely useful if you want to find a specific piece of information without having to scan the entire page.
Keep in mind that this shows the last time the page was indexed, so sometimes images will not show up and the information will be out of date. For most quick searches, that doesn't matter. You can always go back to the current version of the page and double check to see if the information has changed.
Google Syntax to View the Cache
You can cut to the chase and go directly to the cached page using the cache: syntax. Searching for AdSense information on this site would look something like this:
This syntax is case sensitive, so make sure "cache:" is lower case. You also need to make sure there is no space between cache: and your URL. You do need a space after your URL and your search phrase. It's not necessary to put the "http://" part in the URL.
Highlight Terms Without the Cache
The disadvantage of using the cached page is that it may be out of date. Some websites also tell Google not to retain cached pages, so it may not even be an option.
You can use Google to view highlighted keywords on the current Web page by installing Google Toolbar. This is an extension you must download and install to use.