Show a message after the module is installed

After installing this module I went to edit some node meta tags. After saving, I got nothing in my node's HEAD. Same thing with the front page.

It's only once I went to look at settings that I saw that the form elements and output are all disabled by default -- this module does nothing until configured.
Seeing the form elements as uid 1, but no output, was confusing; it would probably have been even more so if I'd been logged in as another used and seen nothing at all.

If it's really this module's design to have nothing enabled by default, I suggest a drupal_set_message on installation, directing the user to the admin page.

Eg

'Nodewords has been enabled. You should now <configure which meta tags to use on your site>.'

_{[Edited by kiamlaluno to show the part of the last sentence that was not shown]}