AdMob, a San Mateo, Calif.-based mobile advertising company, said today that it’s buying AdWhirl, which lets publishers switch between ad networks on the fly, for an undisclosed amount. The acquisition comes in the wake of AdMob moving to pull itself out of AdWhirl’s network and marks a significant consolidation within the mobile ad industry, which is set to hit nearly $2 billion by 2014.

AdMob will not only keep Menlo Pak, Calif.-AdWhirl’s existing ad network, but will release open-source developer tools for it, the details of which it will provide in the coming weeks. AdWhirl’s tools can still be used by app developers in the meantime.

“By offering this first ever open source ad mediation solution, our goal is to provide a much needed open, unbiased and transparent tool for mobile publishers who would like to build financially rewarding businesses that are fueled by advertising,” said AdMob CEO Omar Hamoui in a company statement announcing the acquisition.