I discovered that pool.com maintains a list of domains that are set to expire. I download and filter the list and then email myself a list of domains that match my requirements (.coms under a certain length, no numbers or other funny characters, maybe .coms with a specific word in them). I actually just wrote this script, it had been on my to-do list for over a year. The daily email contains hundreds of domains so I might have to filter it more.
Here's my script, it only uses PHP to get tomorrow's date, otherwise it's standard linux utilities like wget, egrep, unzip, cut, sed...
I have it set up as a daily cron job.
I'm interested in suggestions on how to snipe/reserve/etc domains as soon as they become available.