I can't go through all the steps in a lot of detail here but I can give a basic overview.

I already had a development environment set up for Google Appengine on my computer. This uses PyDev in Eclipse. I'm not much of a Python programmer but I've done a little bit for Appengine, mostly just following the Google tutorials. For my robot, I created a new Google Appengine project and I created a new project hosted on Google Code (using Subversion because I'm comfortable with it). You can see the code for Q&A bot in my qnabot project.

I have a website that I use for stuff but not stuff on the public web. I use it for serving my calendars and private web applications. I use Apache's built in authentication to keep it from being crawled and to keep casual visitors from wandering in. I have a domain name assigned to it from dyndns.org for convenience. The ddclient script runs on one of my boxes and updates the ip address over there whenever mine changes. The system works very well. Most of the time. Somehow one weekend the domain name was left pointing at my old ip address for a while when I was out of town. Who ever had that IP address sure was serving up a lot of nasty stuff. Now Google thinks all that nasty stuff is on my private domain.

I'm going to fix it. I use Google Webmaster Tools for other stuff and I see there's a URL removal tool in there. To use the tool you have to verify that you own the domain - a reasonable request. The thing is the URLs I want to remove are on a domain that I don't want Google to crawl and the way Google verifies that you own the domain is by retrieving a specific URL from the domain. What a dilemma.