As competition continues to heat up in the mobile advertising space, independent ad network Jumptap today announced it is replacing its CEO with an executive from one of its lead investors.

George Bell is taking an indefinite leave from his duties as a managing director at venture capital firm General Catalyst to take the role of CEO. Former CEO Dan Olschwang will remain on the Jumptap board.

In a press release, the company says Bell will advance the company’s growing future as a platform agnostic mobile advertising network. 

Prior to his role at General Catalyst, he served as CEO of Upromise, which was sold in 2006 to Sallie Mae. Before that, he was chairman and CEO of Excite@Home, bringing together the Excite portal with the @Home cable broadband platform in a $7 billion merger. Bell was CEO of Excite prior to the merger, led the company’s IPO, oversaw the acquisition of more than 30 companies and expanded Excite into a worldwide media property.

Earlier, Bell founded The Outdoor Life Network (now Versus Network), a specialty cable channel reaching 60+MM homes. He has won four Emmy Awards for his work as a producer and writer of documentaries.

According to Bloomberg Businessweek, Jumptap is growing even as bigger rivals like Apple and Google invade the mobile ad sector. Citing figures from IDC provided to Businessweek.com, the article says Jumptap may see its share jump to 13 percent this year, from 10 percent in 2009. Millennial Media may rise to 11 percent, up from 9 percent. IDC puts Apple’s share at the end of the year at 21 percent, and Google’s share will drop to 21 percent, from 27 percent last year. Microsoft will drop to 7 percent from 10 percent.