It's quick and easy, but not great if you will be making changes to your article after you insert the map.
1 In Google Maps, click on the link map, customize the map size, then copy the HTML
2 In Joomla, go to site manager - User Manager and change user editor to 'No Editor'
3 Open your article and paste the HTML from Google Maps into your article.
4 China really sucks if you're trying to do anything on the internet.
The big problem with this method is that you can only make changes to your article without an editor (like JCE). If you make changes with JCE, your map will disappear. I always make the map the last thing I put into an article. If you want something more stable, try my Google Maps plug in tutorial