Live Chat: This morning Ask the Headhunter author Nick Corcodilos is hosting a discussion on Negotiating Compensation: Just say No in the IT Careers Chat Room. Mr. Corcodilos will give his views and answer questions, beginning at 11 a.m. PST. (Registration is required, but it’s free.)From the Test Center: Today, it’s part 3 in our series A developer’s-eye view of Leopard. This installment brings a look at Cocoa and other object-oriented frameworks. “Even when Apple supplies several approaches to achieving the same end in order to accommodate developers’ various preferences, the company ensures that all those tactics result in a completely consistent user experience,” writes Tom Yager. One standout that Mr. Yager addresses is the way that “Leopard incorporates changes to its file system to support enhancements to Spotlight and to enable Time Machine automated backup.” Related: Leopard preview, part 2. The news beat: Under heavy criticism, Yahoo CEO Terry Semel steps down and the company says that co-founder Jerry Yang will take the helm. Apple upgrades the iPhone with longer battery life and a touch screen of so-called optical-quality glass. And Jim Zemelin, executive director of the Linux Foundation, says that Microsoft is not going to sue any of its customers because doing so “would not be in their business interest.” Careers