A few weeks ago at SES, Google told me they were going to be allowing advertisers to add logos and graphical images to the mapping balloons that appear on Google Local. I looked for them but couldn’t find them. Today, apparently, they started appearing. This blog has a screenshot. I was unable to find this ad (or other similar ads) on my own.
My understanding is that this doesn’t cost anything beyond the keyword bid; it’s a kind of a perk to marketers. (It’s also an enticement to advertise.) Yahoo! has been doing a version of this for a long time, although the branding is not presented the same way.
This is really just the beginning. AdMission Corp. has a directories module (like a mapping balloon) that can host photos, chat, e-commerce, e-mail forms, even video. I would expect to see all those options and PPCall or click-to-call functionality integrated into these mapping balloons over time.