Dave Grohl Singing Technique?

Hey I'm a newbie here and I wanted to know how Dave Grohl from Foo Fighters sings. In his songs, Dave sings with a bit of distortion. How do you do that? According to Ken Tamplin, Dave learnt this technique from Ron Anderson.

The most apparent and obvious example of his singing style is from their song "Best of You"
Best of You: http://www.youtube.com/watch?v=h_L4Rixya64&ob=av3e

Thank you!