We're in the right market at the wrong time. Hold this long and put your grandkids through college

US mobile ad spending is projected to reach nearly $1.7 billion in 2008, up some 89% from $878 million in 2007, and will surpass $6.5 billion in 2012, according to a new eMarketer report, “Mobile Advertising: After the Growing Pains.”

Even though mobile advertising did not break into the mainstream during 2007, important groundwork was laid as key product launches and announcements gave mobile a boost, eMarketer said, citing Apple’s iPhone and Google’s Android mobile operating system.

The vast majority of mobile ad spend for the foreseeable future is expected to consist of placements in text messaging, which is expected to account for 88% of 2008 mobile ad spend:

That proportion is expected to decrease to about 69% in 2012, with mobile search advertising accounting for nearly 23% and mobile display ads making up 8% of ad spend.

Advertisers worldwide are expected to spend more than $19 billion on the platform in 2012, compared with $2.7 billion in 2007 and $4.6 billion in 2008:

In 2012, the vast majority of mobile ad spend - 74% - is expected to be spent on text-messaging campaigns:

“The US will continue to be the most dynamic region for mobile web advertising because of its position as the largest interactive economy,” said John Gauntt, senior analyst and author of the report.

However, eMarketer expects Asia-Pacific to pull ahead in total spending by 2012, largely due to the huge middle classes in China and India who use mobile as their primary interactive screen.

(Also see eMarketer’s previous mobile forecast.)