Linux Infrared

Two different approaches to join the Infrared world from linux :

• The IRDA project offers linux kernel drivers (including support for some usb based infrared transceivers), and a set of user level tools. It is included in the 2.2.x and 2.4.x linux kernels.
  
• The LIRC project is based on hand-made devices using serial, parallel, and sound ports. It covers many more scenarious while it lacks support for usb based transceivers. If you want to hack around with hardware and build your own infrared devices, this is your way to go.
  

It is possible to sniff infrared traffic, for the adventorous ones.

This magic hardware gadget is an Infrared to/from Sound converter. You sniff on an infrared device (your TV controller), save the converted sound file in an iPod, and when you hit play, the gadget (which plugs into your Earphone jack) converts the sound file back into its original Infrared signal. cool!

This is an excellent source to many IR related links.