Last week, we looked at some research from ZenithOptimedia, indicating that Facebook is on pace to leapfrog Microsoft in online ad spend this year.

“Since 2006 Facebook has established itself as a major supplier, increasing its market share from just 0.2% to 3.1% in 2010,” the report says. “Last year Facebook doubled its share and overtook AOL; at its current pace of growth it is likely to overtake Microsoft by the end of 2011.”

And that’s without Facebook doing mobile ads. A new report from Bloomberg, citing “two people with knowledge of the matter,” says Facebook plans to push into mobile advertising by the end of March, ahead of its IPO.

You can see how ad spend with Facebook has grown over the past several years in the chart above. Now imagine how mobile will fuel that, not to mention the growth in mobile advertising we’re sure to see.

Still, as indicated in a new report from eMarketer, you can see how much of ad budgets are being dedicated to mobile, at least here in the US:

Not much.

That will change though. Eventually, advertisers are going to wake up and realize that they need to be on mobile. Look at the “time spent share” for newspapers and magazines compared to mobile, and how the ad spend stacks up. Doesn’t make a lot of sense does it.

Facebook ads in general are very attractive to advertisers, however. That’s why the channel is growing so rapidly. The company has targeting capabilities that are pretty much unrivaled (though some governments aren’t crazy about that). With mobile, it should be easier to match with physical location targeting.

This should be a pretty good source of revenue for the social networking giant, and will likely get advertisers more interested in mobile.

Separately, Facebook is reportedly testing some new coupons and ads.