SAN FRANCISCO -(Dow Jones)- For want of a few key details from Microsoft Corp. (MSFT), Joel Spolsky tried but failed more than 10 years ago to make a better version of Microsoft's remote office desktop-computer feature.

Now Project Co-Pilot has gotten new life. On Thursday Spolsky finally located those elusive lines of code tucked inside 30,000 pages made public Thursday by Microsoft. Before they were available only under trade-secrets licenses.

"It took me only five minutes before I could find something I could use," said Spolsky, Microsoft's Excel program manager in the 1990s, who now heads Fog Creek Software Inc. based in Manhattan.

By sharing more technical information about its key products on Thursday, Microsoft has jump-started a wave of development destined to unleash software that will compete with many more of Microsoft's own products.

One of the first appears to be remote desktop software, which uses a secured Internet connection to remotely access files and features stored on office- desktop computers.

Currently, there's no third-party version of the software, save for Citrix Systems Inc. (CTXS), which has a cross-licensing deal with Microsoft. But Microsoft's existing product is a very basic one, making it rife for improvements. Its relative simplicity is demonstrative of how there's been no competitive offerings that would have forced Microsoft to make a better widget.

Another oft-mentioned favorite is open-source versions of products that compete with the Windows subsystem of goods. That's been tried in the past, without much luck, using open-source Linux software.

"Things will get real interesting then," Chapman said.

The question about this new strategy, which no one can answer now with much assurance, is at what cost this will have to Microsoft.

On Thursday, Yankee Group analyst Laura DiDio argued it could be in the billions of dollars, particularly in lost software-licensing royalties. Rick Chapman, editor of the Softletter software-industry newsletter, said the damage may be only in "millions of dollars."

Microsoft Chief Executive Steve Ballmer didn't put a dollar figure on it during a conference call with journalists, but did concede there were both opportunities and risks.

"We think the impact on Microsoft's financials is unclear because it will face increased competition in selling complementary software," said Jim Yin, Standard & Poor's Equity Research analyst.

Microsoft shares are currently down 20 cents to $28.01 on volume of 85.4 million compared with average daily volume of 83.1 million.

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

  (END) Dow Jones Newswires
  02-21-08 1608ET
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