On http://drupal.org/project/simplenews_register you have

- Configure "Simplenews on register" on the Simplenews admin pages. There will
be an additional fieldset at the bottom:
Administer > Content Management > Newsletters > Settings.

where it should be like on README.txt

- Configure "Simplenews on register" on the Simplenews admin pages. There will
be an additional fieldset at the bottom:
Administer > Site configuration > Simplenews > General

I would suggest moving all the documentation into a single location (README.txt, project homepage or handbook page) and link all the other places to that. This will avoid issues like this.

JM2C

Fabio Varesano