I have been a long time reader of TidBits - a web site dedicated to dispersing and distilling Apple-related news for many years. In recent years the TidBits team also launched TakeControl Books. These are full length eBooks in PDF format (no DRM) covering a variety of topics.
Most recently I purchased a Garage Band book from the site for use in the musical side of my life (music studio and local performances). However, covering the Mac as it pertains to financial services on this site and also recently upgrading to Snow Leopard - I wanted to point out some new releases in the last few weeks.
Download a free sample of the Upgrading to Snow Leopard book, which includes a table of contents and sample chapter material.