Hubert Matthews talked at the this year's ACCU conference in Bristol with lot's of examples and detailed insight about:

The Dos and Don'ts of Multithreading

by Hubert Matthews

From the conference's schedule:

Multithreading is a popular subject and we've all been led to believe that we need to write threaded programs as single-threaded performance hits a ceiling. However, multithreading is no panacea and may cause more problems than it solves. This talk, suitable for programmers of any level and language, seeks to describe some of these problems and also how to avoid them through appropriate design choices.