Shares of Infosonics ( IFON) were among the biggest winners in technology Thursday, rising 17% after the wireless handset seller renewed a distribution agreement with Samsung Electronics.

The agreement, which runs through Dec. 31 of this year, calls for Infosonics to distribute Samsung devices in Argentina, Paraguay and Uruguay. Shares of Infosonics recently were up 84 cents to $5.84 on volume of 6.7 million shares -- more than 12 times the average daily volume of 540,000 shares.

Shares of Microvision ( MVIS) jumped 18% after the company said it plans to demonstrate an ultra-thin color projection display for mobile devices. The company said the display could be embedded directly into mobile phones or be used as a stand-alone accessory. The product will be unveiled at the Consumer Electronics Show in Las Vegas next week. Shares of Microvision were up 58 cents to $3.65.

Witness Systems ( WITS) shares jumped 13% after the software maker projected revenue above Wall Street's forecast. For the recently ended fourth quarter, the company estimated revenue of $63 million. Adjusted revenue, which excludes hardware sales, is expected to total $62 million. Analysts polled by Thomson First Call had an average forecast for revenue of $58.2 million.

For 2007, Witness Systems sees adjusted revenue of $250 million to $255 million. Wall Street expects revenue of $246.8 million. Shares were trading up $2.32 to $19.83.

Shares of Sigmatel ( SGTL) slid 11% after the chipmaker cut its fourth-quarter sales estimates and announced the resignation of its chief executive. The company projected fourth-quarter revenue of $37 million to $38 million, below its October forecast of $41 million to $46 million. Analysts targeted revenue of $43.8 million.

Sigmatel said that Chairman, President and CEO Ronald Edgerton resigned to "spend more time with his family." The company named board member William Osborne chairman. Phillip Pompa, the senior vice president of the company's portable systems group, will become interim CEO. Shares of Sigmatel were down 51 cents to $3.99.

Other heavily traded tech stocks Thursday included Intel ( INTC), up 78 cents to $21.13; Cisco ( CSCO), up 44 cents to $28.17; Sun Microsystems ( SUNW), up 10 cents to $5.64; Microsoft ( MSFT), down 1 cent to $29.85; Sirius Satellite Radio ( SIRI), up 2 cents to $3.76; Level 3 Communications ( LVLT), down 7 cents to $5.58; Apple Computer ( AAPL), up $1.47 to $85.27; and EMC ( EMC), up 25 cents to $13.45.