Advertisements keep free radio, tv, and web sites alive (including this one!). So, you won’t find me complaining about Google/YouTube introducting ads to their YouTube mobile site (m.youtube.com).
YouTube calling: Now serving ads on the YouTube mobile site (The Official Google Blog)
Google notes that ads should show up on the U.S. and Japan YouTube mobile site. The ads should show up between the Home/Videos/My Account tabs bar and the Spotlight Videos bar of the mobile site. However, as you can see in the photo I took of my iPhone and Nexus One sitting side-by-side displaying the YouTube mobile site, it hasn’t shown up everywhere yet.