Based on the Step-by-step: Speed Up WordPress with Varnish Software article originally written by Federico G. Schwindt and published on Web Designer Magazine - http://www.webdesignermag.co.uk/ as well as on the Varnish Software blog.
It is now available in the Varnish Web Developer Wiki, specifically under the Varnish with WordPress Tutorials section. As with any other wiki docs you can help us to expand it and keep it up to date. I'm publishing it here in the blog for reference. Read on:
With web 2.0 and the growing popularity of social media, websites were put under a lot more stress. Delivering content fast and reliably is a relevant challenge. In the hosting industry (I work at Combell, the leading Belgian web hosting company) we no longer just talk about throwing servers at the problem. Offering fast, stable, secure, scalable and affordable solutions to clients has become the core business.