Usability 
James Kendrick is one of my favorite mobile tech bloggers. He's also one of the first. As his blog jkOnTheRun's tagline used to say, he's been "using mobile devices since they weighed 30 pounds". James covers just about every significant mobile gadget and software release with insightful reviews and analysis and wraps up the week's top mobile news every Friday in a 'Mobile Tech Manor' post.
After a stint with the GigaOm network's family of tech blogs, James has moved to ZDNet writing under the "Mobile News Blog" banner and continuing his weekly summary, now titled "Mobile News Manor".
A nice plus of the move to ZDNet is that the blog gains a mobile formatted version, something the GigaOm blogs lack. The single column mobile version retains all the text and image content of the desktop version.