Google today closed its acquisition of AdMob, the mobile advertising network. Mountain View reportedly paid $750 million for AdMob.

Google’s purchase of the company was stalled when the FTC said it was looking into whether the deal violated anti-trust legislation. The FTC’s decision to allow the sale to go forward was in part due to Apple’s purchase of AdMob competitor Quattro wireless, and Cupertino’s subsequent rollout of its iAd network.

In a blog post on Google’s Web site today, Susan Wojcicki, vice president of product management, said the first step will be to orchestrate a quick integration of the two companies.

Wojcikci echoed sentiments from around the industry that see Google’s acquisition of AdMob as huge boost to the legitimacy of mobile advertising.

“It’s clear that mobile advertising is becoming a much larger part of our clients’ and partners’ strategies and with this acquisition, it’s now a central part of our own business,” she wrote.

Wojcicki said that Google’s mobile search volumes have grown more than fivefold over the past two years. In the first three months of 2010, people with smartphones with “full” WebKit browsers (such as the iPhones, Android devices and Palm Pre) searched 62 percent more than they did in the previous three months.

As for the future, Wojcicki said the plan is to expand mobile advertising to all mobile devices.

“We believe that mobile advertising can play a significant role in every single marketing campaign. We’re passionate about the unlimited possibilities in this space. Today, with AdMob, our work to make them a reality begins,” she wrote.