At the last meeting I demonstrated the use of the Enhance > Convert to Black and White… tool for converting images to black and white. While this tool is still a perfectly acceptable way of doing this, I have since discovered this tutorial that uses a different, in many ways better technique for this.
If you would like a refresher on the demonstration I gave, there is a two-part video tutorial here that you can take a look at. Please note though that this video uses Photoshop Elements 5 and the conversion dialog has changed since then, with the thumbnails for adjusting red, green and blue channels, as well as contrast being replaced with slider controls.
The other technique I demonstrated was how to retain only selected areas in colour while converting the image to black and white. This tutorial demonstrates how to do that as well as revealing some other ways of doing the black and white conversion.