Google announced today that it will acquire mobile ad network AdMob for $750 million in stock. This puts the deal near the top of Google’s deal sizes to date.

AdMob is one of the biggest mobile ad networks and is known best for the display ads it places within iPhone apps. Google meanwhile has clear intentions of moving into mobile marketing, but what it’s done so far mostly involves 1. text ads 2. replicating the online search experience (organic + paid results).

AdMob, as a mobile-online ad network that specializes in display ads, will help Google broaden its mobile reach. There’s more to it and more commentary to come. In the meantime, see coverage from CNET and Wall Street Journal (sub. req.).