Researchers at security firm Kaspersky Lab have discovered a virus that can infect Apple’s popular portable media player, the iPod. But users do not have to scramble for protection just yet. The virus would only affect players that run Linux instead of the iPod’s native operating system.

Currently, Linux-fueled iPods are a very small minority because they require users to do the system swap. The malicious program, called Podloso, might not present a real threat, but Kaspersky noted that it does demonstrate that it is theoretically possible to create malicious programs for devices such as the iPod.

Podloso is a typical “proof-of-concept” virus, which is created in order to demonstrate that it is possible to infect a specific platform. Although some users might find it odd that security researchers would ever whip up a virus, the type of concept code developed by Kaspersky is very common, and considered a preventative measure against future threats.

When movies shifted from videocassettes to DVD, retailers simply cleared the tapes off the shelves to make room for discs. That’s not so easy now that movies appear poised to follow music onto the Internet.

The shift of music online has hurt stores such as Best Buy, Wal-Mart and Circuit City, and some retailers are looking to avoid a repeat with movies. Wal-Mart has launched its own movie download service, Best Buy is said to be in talks to start one, and Blockbuster explored buying movie download company Movielink earlier this year.

Music and DVDs are important to retailers because they’ve traditionally driven customers to stores. Each week’s new releases give people a reason to come back. And for electronics retailers such as Best Buy Co. Inc. and Circuit City Stores Inc., discs are often a cheap impulse sale, unlike a pricey computer or TV.

Time Warner Inc.’s AOL division will introduce a paid search service on Monday backed by Google Inc.’s technology to help advertisers better target AOL users.

AOL Search Marketplace is part of a December 2005 agreement with Google in which the Web search leader purchased a $1 billion stake in AOL, the online division of the world’s largest media company.

As part of the deal, sponsored links from Google’s AdWords technology appeared on AOL Search pages. AOL Search Marketplace, a customized version of AdWords, now lets advertisers reach AOL Search customers more effectively, AOL said.

The service will help AOL capture advertising dollars from ads linked to search terms in text, in addition to the money it makes from display ads, such as banners. AOL’s search service drew 311 million queries in February, according to tracking firm comScore Media Metrix.

“If I’ve got a relationship with a big marketer and half of their interactive ad spending is going toward something I don’t offer (search advertising), I’m going to want to acquire that capability,” AOL Media Networks President Mike Kelly said in an interview.

Google Inc. is out to make map-making simpler, giving away tools for ordinary users to pinpoint locations, draw routes and attach photos or video to existing online maps, the company said on Wednesday.

The Web search leader, which set off an explosion of creative map-making among professional programmers after introducing Google Maps two years ago, is now offering MyMaps, tools for everyday users to create maps in a few mouse clicks.

Let your imagination run wild, spatially speaking: Pinpoint your favorite restaurant locations. Return from a world tour and plot out landmarks along the way. Take photos from a recent hike and use MyMaps to illustrate locations along the trail.

“Who better to create maps than local experts?” Jessica Lee, product manager for Google Maps, said in an interview. “MyMaps makes map-making universally accessible to anyone.”

Online advertising company DoubleClick Inc. said on Wednesday it will launch an exchange to connect buyers and sellers of digital advertisements in the third quarter.

The DoubleClick Advertising Exchange service is currently being tested in the United States and is expected to be available globally by the end of 2007, the company said in a statement.

Microsoft Corp., Yahoo Inc., Google Inc. and Time Warner Inc.’s AOL unit have been reported to have expressed interest in purchasing DoubleClick, which is majority-owned by San Francisco-based private-equity firm Hellman & Friedman.