For 1,000 users, the basic Safari online service starts at about US$170 per user, or about $170,000, said Dennis Kilian, Safari's vice president of sales. For the premium service, which allows users to download the online books to their hard drives, the service begins at about $220 per user for 1,000 users.

The idea to offer the online books as a complete online library came from customers, Kilian said. "It came up in discussions with larger customers," he said. "They said they wanted to be able to offer it to their workers."

Other enterprise users have signed up for the service but are not being named, he said. "There are several large technology companies using this and several large financial institutions."

Michael Norris, a senior analyst at Stamford, Conn.-based publishing industry analyst firm Simba Information Inc., said online technical books are a good idea, since such information is quickly out of date because of the fast pace of technology. Overall, the publishing of technology books on paper has been down for several years because they haven't been selling well, he said.

"I think what Safari Books is doing is really cool," Norris said. "People don't want to pull a dusty book off the shelf anymore."