for a quick and dirty solution you can simply use Phil from UK MOds free RSS feed mod and then all you do is set up a feed from your blog that is displayed within your xcart.
You can control how many characters are displayed in the feed and then the user can simply click through this to your blog...
You can see this on the home page of my
www.CoffeeShrine.com.au site though you may want to display the feed in the centre section of your site and display mroe characters