Microsoft and Siebel Systems Inc. last week expanded an alliance to put Siebel's market-leading CRM software on Microsoft's .Net platform. Under the terms of the three-year, $250 million deal, more than 100 engineers from the two companies will work to make sure Siebel's programs run well on .Net. Microsoft also will help develop Siebel's Universal Application Network, an effort to make it easier for businesses to integrate enterprise applications.

The effort should lead to cheaper, better connectivity, Microsoft chairman Bill Gates says. Tighter links between Microsoft's Office apps and Siebel Smart Client and eBusiness software are planned.

Siebel last week also disclosed a renewed relationship with Sun Microsystems, backers of a competing technology, Java 2 Enterprise Edition. Scott Anderson, a global alliance director for Sun, says about 10 Sun and Siebel engineers are working together on product development, marketing, and sales.