WordPress has a feature that will allow you to display an RSS feed to your blog. This is very useful especially if you want your readers to know what is your latest post and when you post it. Readers are more interested in blogs that update frequently than those that leave their blogs for months and update on an infrequent basis. This built-in widget is a great tool for letting users know what you are up to. However, the problem is it does not update as often as you update your blog. Here is a quick hack that you can do to change how often your RSS feed will refresh.
Full article here: http://www.wprecipes.com/how-to-force-the-rss-widget-to-refresh-more-often