My wife and I have a wiki that we use to keep track of our projects and our business ideas. It’s a great way that we can collaborate anytime/anywhere over the magical global intarweb.

We have a section for each of our active businesses as well as an area that has a laundry-list of all of our potential ideas. Its also a great spot to keep lists of potential domain names.

If you need more info about starting a wiki, wiki books is a great resource. They even have a list of sites that let people create a free wiki. If you want to have a password protected wiki, you could try PB Wiki.