Up until a few weeks ago, I'd had the same mobile non-smartphone phone for over three years, never feeling the need to upgrade.  It finally passed away, and I took the plunge into the world of Windows Mobile, getting a Dash which I'm now enjoying immensely.  This has also renewed my interests in writing applications for mobile devices, and more specifically porting applications I've already written for the desktop to work well on my phone.  This made the July 2007 issue of MSDN Magazine all the more relevant to me, with Daniel Moth's really useful article Share Code: Write Code Once For Both Mobile And Desktop Apps. It discusses techniques and principles that can be utilized when writing cross-device code—applications that target Windows devices with differing form factors.  If you haven't already seen it, it's worth a read.

-Stephen