I've just installed a fresh copy of WP 2.0.3 from the tarball, in a separate subdirectory of my blog host (for you to check). Then I've downloaded the es_ES.mo file from the lang repository, installed it into "wp-includes/languages" and finally edited /wp-config.php to say "define ('WPLANG', 'es_ES');"
Problem is changes were not reflected. I've been searching through the forums and noticed the default theme is not gettexted so I got a version from Maira and installed it: It didn't work, either.
Then I tried the Classic theme, which also is gettexted: still no results at all.
Can you please point me into the right direction?