There is a set of two books: Linux Toys and Linux Toys II which offers a geek way to computerize your home. Both books describe a few open source projects which can be used by home users for some purposes: automation, entertainment, hosting for data, movies, pictures etc.
From the first part of the Linux Toys I’d like to emphasize (in respect to smarthome) Music Jukebox, Temperature Monitor and Home Video Archive projects. But note that there are many newer and better open source applications to do the same things (the boos was published at 2003).
Since Linux Toys II is newer then Linux Toys (November 2005) it contains a few interesting modern projects such MythTV and Icecast. It might be useful to read a chapter 7 – “Automating Home Lights and Gadgets with X10” for automation fans. The rest projects are related with smarthome but not so strongly as I’d like.
Anyway, for me those books were useful to give some ideas and hardware supported by Linux. You can get all information directly from the open source projects used there. And those information will be fresh. For example, I found DigiTemp software and a bunch of 1-wire and iButton hardware to build weather station based on Linux in the Linux Toys. There is a simple example which can be extended into profession solution.