A few weeks ago I ordered the Neo1973 phone and have been playing around with it a bit since. The software is currently early alpha state and often fails to even build correctly, but that's what we all expect at this early phase of development.
The easiest way to build a complete image to flash on the phone has been to use Rod Whitby's MokoMakefile. Basically all you have to write is "make openmoko-devel-image" and wait a few hours. To compile the whole OpenMoko distribution from scratch takes about 10 hours on my AMD64 3000+, so it's not something you just do in a heartbeat.
The OpenMoko Wiki is really working well and it's still expanding quickly. #openmoko on Freenode is also a very busy channel, currently around 320 people in it. There's always someone there to point you in the right direction if there's some trouble with your Neo.
I have yet to make any applications on my own to install or include in the rootfs, but I'm trying to keep up with the latest development and I'm still learning how bitbake works.
I haven't even been able to make a call with the phone yet, or been able to use the GPS. But that's fine for now, I did order a development sample of a phone. The battery on the Neo doesn't last long either since the power management isn't really working yet. Basically it can be on for a few hours, then it dies completely.
The screen looks great though, and the size is nice. The touchscreen feels good, but is a bit difficult to use near the edges. It's definitely a bit slow to use still, but the GTA02 version (mine is GTA01) will have some nice additions, including WiFi, 3D Graphics accelerators and a faster processor.
There's still a lot of people ordering the developer version of the phone and I'm sure that we'll see a lot of interesting applications fairly quickly. I do worry a bit about the stability and quality of it though. Hopefully they will lock down a stable release in good time before the public release of the phone so that there's enough time to test and bugfix without introducing more problems.
I have no doubt that there will be lots and lots of games and utilities for this phone in a years time. The Neo1973 is still only for tinkerers who like to mess around, but the future is promising.