Shades of Gray: Thoughs on Sketching by Will Evans is a worthwhile read to understand the role of sketches and wireframes in the software and web design process.

I use an A4/Letter size (or larger) sketch pad to illustrate interfaces and note down thoughts while brain storming interface and communication/interaction solutions before I start producing digitally created wire frames.

The link to the article is:

http://blog.semanticfoundry.com/2010/01/31/shades-of-gray-thoughts-on-sk...