I'm not sure if this has been updated or not, but writeroom crashed my Leopard install this morning. I was going through all my third party apps and gave writeroom a try... it failed to launch and then nothing else would launch either. I had to hold down my power button to shut down my mac and reboot.
After which spotlight had to rebuild it's index
Weird.
UPDATE: Looks like there's been up update to writeroom already that fixes the problems:
Leopard Woes