This naming convention is one of the patterns in Kent Beck's book Smalltalk Best Practice Patterns. IMHO this book is a must-have even for non-smalltalkers, as it really helps naming things and writing self-documenting code. Plus it's probably one of the few pattern langages to exhibit Alexander's quality without a name.
Another good book on code patterns is Smalltalk with Style, which is available as a free PDF.
Generally, the convention is that instance variables and accessors use the bare noun, and parameters use the indefinite article plus either a role or a type, or a combination. Temporary variables can use bare nouns because they rarely duplicate the instance variable; alternatively, it's quite frequent to name them with more precision than just an indefinite article, in order to indicate their role in the control flow: eachFoo, nextFoo, randomChild...
I already got some hand printed year calendars from crispinfinn.com (http://farm3.static.flickr.com/2595/3931755944_2259ef928a_b.jpg). I'm also getting A Pattern Language for an architect interested dad (http://www.amazon.co.uk/Pattern-Language-Buildings-Construction-Environmental/dp/0195019199).