On a related note, I live in a high rise condo in Milwaukee. There are a ton of hotspots. I left mine wide open, in the spirit of sharing.
The other night I was having bad problems with speed. My connection was up and down as well. I decided to look into it, and I had 12 freeloaders on my WAP. I decided to kick them off go to WPA encryption. Speed and connections are both looking up.