Barry Schwartz mentioned last week that Google tests a new position for search ads. The ads stay closer to the organic results and they're no longer next to the scrollbar. The experiment was probably successful and the change should be visible to everyone.
Google also started to show related searches below the ads and the suggestions are commercially-oriented. It's a good way to show more relevant ads and to determine the user's intention.
Some of the ads display product listings from Google Base and Google shows a thumbnail next to the list of products.
Update. Daniel Dulitz, from Google, has an interesting comment: "It would be easy to just increase revenue. What is hard is to make ads appropriately visible when you want to see them without being in your face when you don't want to see them. People are smart -- users ignore banner ads because they've proven useless over time -- so if you just make ads more visible, without regard to their utility, it's doubly self-defeating. Very tricky business."