ChaCha, the free SMS-based real-time answer service, announced an additional $20 million round of funding from new investors VantagePoint Venture Partners and Rho Ventures.

ChaCha allows users to text a question to a short code. The question is then answered via a return SMS.

In the course of answering questions, ChaCha creates what it calls a “dialog” with users, which ends with a marketer’s call to action. The company says it has plans to deploy a new MMS service that will deliver movie trailers, other video, coupon images and rich media ads to both feature phones and smartphones.

The service counts Paramount Pictures, McDonald’s, Palm, Coca-Cola, AT&T, J&J, P&G, Wal-Mart and Best Buy and others among brands that have run campaigns through its service.

ChaCha reports having answered nearly 1 billion questions in the past two years, surpassing even Google in mobile text search, according to Nielsen.

Since inception five years ago, ChaCha has raised capital from prominent tech leaders, venture capitalists and angels, including Jeff Bezos, Morton Meyerson (leader of EDS and Perot Systems), Rod Canion (the creator of the portable computer industry), Jack Gill (co-founder of Vanguard Ventures) and Don Aquilano (MP of Gazelle TechVentures).

The company’s year-to-date ad sales are up 292 percent. More than 70 percent of ChaCha’s 2010 advertising campaigns to date are renewals.