Open Source for mobile phones is not just cool, but necessary.
Why do I say that? Because it stands to reason. First, "smart" phones and similar ones with PDA functionality cost a lot. You obviously want to be able to keep it going for a few years at least, and not dump that $1,500-$2,000 device simply because there's no choice.
That's currently how it works with many phone makers. My Telecom Apache is great, but the maker, HTC, doesn't provide timely updates for it. Microsoft has released Windows Mobile 6, and it'd be nice to upgrade to that as it has many features I'm keen on but... no. There is no upgrade path for the HTC Apache to WM6.
This silliness points to the current model of proprietary vendor releasing an OS to an OEM who then passes it onto an operator being broken. It only takes one entity in that chain to stop cooperating and customers are stuck with old software that's buggy and insecure.
A standards-based open source solution like OpenMoko could fix all that, and benefit not just customers, but also OEMs and operators.
It's not a pipe-dream either: electronics giant FIC of Taiwan has already produced an OpenMoko phone, the Neo1973. This is a far more exciting development than Apple's proprietary iPhone that locks customers in to what the iJobs allows them to do. I hope it's the first of many Open Source phones!