PopCap Games today announced $22.5 million in new funding -- a significant development since the 9-year-old Seattle company has grown into one of the largest developers of casual games without outside funding. Late-stage investment firm Meritech Capital led the deal, with angel investors John McCaw and Larry Bowman also participating. Meritech is a Silicon Valley firm best known as an investor in Facebook, while McCaw is a former McCaw Cellular executive.

Bowman's involvement in the company was first reported by TechFlash in August after we discovered a filing showing that the PopCap had raised $7.3 million. The filing indicated that Bowman -- once described by Fortune as a Silicon Valley "hedge fund king" -- was also a director of the company. A spokesman said at the time that money was tied to last year's acquisitions of SpinTop Media and PlayTime Media,

In a press release today, PopCap said that Bowman had previously purchased shares in the company by cashing out stock of the company founders. But today's round is the first time that PopCap -- creator of hit games such as Bejeweled, Peggle and Plants vs. Zombies -- has raised money entirely for operations.

PopCap CEO Dave Roberts said the new money would allow the 240-person company to be more aggressive as it expands geographically and launches efforts in social media.

"We’ve been pursued by investment firms for many years and have resisted taking outside capital, but we liked Meritech’s style and believe there’s a tremendous opportunity to grow and evolve our business at a time when many other video game firms are retrenching,” said Roberts.

Big money has flowed into the casual games business in the Seattle area before. Last year, just before the recession hit, Big Fish Games hooked an $83 million venture round.

With the IPO market showing some signs of life, PopCap and Big Fish both could be candidates for IPOs. After all, it is not uncommon for companies to raise capital before a public offering. And late stage firms such as Meritech usually like to see a return on their capital.

For now, it looks like Meritech -- also an investor in Vonage, Salesforce.com, Danger and others -- is just happy to be in the deal.

“PopCap is arguably the most unique video game company on the planet,” stated Rob Ward, managing director at Meritech in a release. “While other video game companies put out more flops than hits, PopCap has never produced a game that wasn’t a critical and commercial success."

UPDATE: The $7.3 million funding that we previously reported was unrelated to the current financing deal. A company spokesman declined to comment further on today's financing, but I am hearing that some of the money will be used to repay loans to existing shareholders.