The "302" status code should be returned by a weebsite when there has been a temporary redirect that should not be used permanently. For example, you may have a bookmark to the Hooterville News newspaper with url
http://www.hootervillenews.com/todaysHeadlines
which you click on to get today's headlines. In response, today, their server may send back a 302 status code and redirect you to the url:
http://www.hootervillenews.com/headlines/2005_07_16
which will give you the headlines for today, July 16. But if you click on that same bookmark tomorrow, you will again get a 302 response but will be redirected to a different url:
http://www.hootervillenews.com/headlines/2005_07_17
which will give you the headlines for tomorrow, July 17.
This example illustrates the correct use of the 302 status code by the Hooterville News. Note that, in this case, you would not want to change your bookmark to point to the redirected url, because if you did, you would be reading July 16's headlines forever.