I am using 2.7 and just added
<?php the_author_posts_link(); ?> to my loop in index.php
The author name shows up on the home page but it doesn't show once you click on "Read the rest of this entry", or in the archives or Categories or any of the Tag Cloud links.
In the past I used this tag or similar on another blog and the author showed up on all the pages. I just don't know what I did differently.
oh yea... the site is http://www.graceunfolding.com