Here’s our roundup of the week’s tech business news. First, the most popular stories published in the last seven days:

Chris Paget at DefconHacker shows how he can intercept phone calls with $1,500 device — A security researcher showed in a live demo at the Defcon security conference how he can intercept cell phone calls with just about $1,500 worth of equipment.

PlayOn brings Hulu and Netflix to the iPhone — without Apple’s help — PlayOn, the service that allows you to view streaming media from the Web and PCs on a variety of devices, finally made it to the iPhone.

iPhone 4 jailbreak lands with JailbreakMe 2.0, no computer required — The moment many intrepid iPhone 4 owners have been waiting for is here: The iPhone Dev Team has released a jailbreak for the iPhone 4 via their JailbreakMe 2.0 tool — and this time around, users can perform the hack right on their device.

How North Korea could build a cyber army to defeat the U.S. — It wouldn’t be that hard for North Korea to build a cyber army to take on the U.S. in a war fought only in cyberspace. That’s the assessment by Charlie Miller, a veteran computer security tester whose accomplishments include hacking Apple’s operating system and the iPhone.

Reformed hacker reveals “My life as a spyware developer” — Garry Pejski’s tale is a cautionary one for young hackers, and it offers a rare glimpse inside the shadowy world of spyware, a massive underground industry that dances on the edge of legality.

And here are five more articles we think are important, thought-provoking, or fun:

Mark Zuckerberg at F818 new ways Mark Zuckerberg rules social networking — Facebook CEO Mark Zuckerberg is already the undisputed king of social networks, but now he has one more prize: 18 key patents related to social networks, quietly purchased this summer from the industry’s faded pioneer, Friendster.

Tesla Motors reports wider $38.5M loss, but says it’s on track — As predicted, Tesla Motors posted higher losses for the second quarter during its earnings announcement this week — its first as a public company.

RIM fights back against the iPhone and Android with touchscreen BlackBerry Torch and BlackBerry OS 6 — We knew that BlackBerry-maker Research in Motion was going to announce something big at its joint AT&T event Tuesday, and it certainly didn’t disappoint.

Google confirms acquisition of social app startup Slide — Google announced Friday that it has acquired Slide, the social application maker headed by PayPal cofounder Max Levchin, confirming reports from earlier this week.

Shopkick’s mobile shopping app tracks you in stores, delivers real-time deals — At the San Francisco Best Buy store, Shopkick founder and chief executive Cyriac Roeding unveiled the company’s free iPhone app that rewards users for visiting partner retailers.