NComputing is launching a new, cheaper version of its low-cost thin-client computers today, computers that it’s targeting at developing nations.

The company’s sold a million units of its X300 desktop virtualization kit in the past two years, but it’s new X550 model promises to make computing even cheaper. The kits consist of a PC connected via Ethernet cables to boxes known as “access devices,” which can connect to a monitor and keyboard and function essentially as a computer. The thin clients themselves don’t have any CPU or main memory chips, so they’re much cheaper than standard PCs but offer much the same functionality.

With the kit, a single PC can support a total of six users — one on the PC and five on the clients — for a cost of $449 (at full retail price). That comes out to under $75 per user. The earlier X300 model supports three access device users plus another on the PC.

The Redwood City, Calif.-based company is headed by former eMachines chief executive Stephen Dukker, who believes there will be even more demand for the machines in the economic turmoil when institutions in developing nations will have even less money to spend on computing systems.

NComputing has gotten considerable attention for its success in snaring contracts to provide computers to schools and government bodies in developing nations, and we recently covered the company’s deal to provide up to 50,000 clients for children in schools in India.

With two of the X550 kits, NComputing can support 11 users — 10 access devices, plus one user on the PC. (By comparison, two of the X300 kits supported seven users on a PC.) Each X550 kit includes five access devices (monitors not included), a PCI plug-in card, and the company’s vSpace virtualization software, which distributes the PC’s processing power across the clients.

The access devices also save on electricity costs, since they consume 1 watt of electricity compared to 85 – 110 watts for a standard PC. The kits can run a full suite of Windows or Linux applications.

The company has deals with 25,000 organizations in 100 countries so far. Ncomputing was founded in 2004 by a team in Germany and South Korea. Besides the $8 million first round led by Scale Ventures, the company also raised $28 million in a second round led by Menlo Ventures earlier this year. It has 160 employees.