One of the easiest ways to upgrade between version 6 and version 7 of Drupal is to re-build your site in Drupal 7, and then use the Views Data Export and Feeds XPath Parser modules to move your pages and articles into your new site.
This post shows you the details of setting up both a D6 View you can export and a D7 Feeds importer you can use to migrate that View content.
Update: You might find the code attached to the "Feeds is my Friend" post helpful in supplementing these instructions. And I now recommend using the Features module to make it easy to copy Content Types, Taxonomies, Menus, and Feeds Importers from your test to production sites.
If you notice anything missing or confusing in these instructions, please send me a note, so that I can improve this tutorial. Thanks!