A easy way to upgrade and then very easy way to just upgrade it after that is use svn.
Make a new folder like. WordPressNew
cd to it and do this command:
svn co http://svn.automattic.com/wordpress/tags/2.3.3
It will install all the files to 2.3.3 WordPress.
Copy your wp-config.php and new stuff in your wp-content folder to the WordPressNew folder. Any other folder files you added like plugins, copy them over too.
Then just go to the new WordPressnew in your web browers and add /update at the end. You can go on from there to set it up.
You can delete your old WordPress folder then and rename the new WordPress folder to what your old one was.
Then to update all you have to do is log in and cd to your wordpress foler and do this command:
Or go to http://svn.automattic.com/wordpress/tags There you can see numbers and to update to that number do this command:
svn sw http://svn.automattic.com/wordpress/tags/2.3.3/
Or it my be
svn sw http://svn.automattic.com/wordpress/tags/2.3.4/
You can get a list of what's out at that web link.
That makes it easy to update. It only updates the files that changed so it will not even tuch your files like wp-config.php
You can do a:
It will show files it will not update with a ? at the start.