Online retailer Amazon.com Inc. (AMZN) plans to distribute 200 more videogame downloads for Sony Corp.'s (SNE) PlayStation consoles.

The new agreement between the two longtime partners helps both adjust to the growing popularity of downloading games from the Internet, rather than buying videogame software stamped onto discs. While online distribution is still a nascent market, videogame makers see it as a growing part of their business.

The deal, announced Wednesday, calls for Amazon.com to sell tokens redeemable at Sony's PlayStation Network, which is an online bazaar stocked with games for PlayStation game consoles, and the portable PSP. It marks the first time since the network opened in 2006 that another retailer, online or otherwise, has sold the tokens.

For Amazon.com, the deal "expands our current library of videogame downloads," Amazon.com Vice President Paul Ryder said in a press release.

Sony, meanwhile, said it sees the partnerships as key to how its retail partners already selling the PlayStation and other Sony game products will take part in Sony's digital distribution plans.

The company continues to talk its other retailing partners about the same kind of deal, said Peter Dille, a Sony senior vice president who oversees the PlayStation Network. "We would have a similar discussion with anyone else currently selling PlayStation products," he said.

Amazon.com ended regular trading up 3.3% to $93.97; Sony added up 1.6% to $28.09.

-By Ben Charny, Dow Jones Newswires; 415-765-8230; ben.charny@dowjones.com