Former Netscape Communications CEO Jim Barksdale and former Microsoft executive Brad Silverberg have invested an undisclosed amount in start-up Tellme.com, sources said. The company has not disclosed details of its business, but sources said it is creating technology that consumers will be able to use with their telephones, expected in the first half of 2000. Silverberg and Peter Currie, former Netscape CFO, also have joined Tellme.com's board, the sources said.