On last Wednesday, I participated at the August Sevilla Drupal Group monthly meeting, talking about my experience contributing to Drupal.
We walked through how to contribute translations, the modules and themes contribution approval process, how to report issues, how to contribute a patch and how you could become involved in the on progress Drupal Initiatives. We also did a quick review on what we can expect of Drupal 8.
The slides I used are based on Webchick's "One Drupal 8 Slide Deck To Rule Them All". For the reference, they are available on Slideshare: Contributing to drupal from Christian Lopez
I saved on Del.icio.us too a collection of the links we looked at.