I've been reading about Linux Kernel development / device drivers and all of the books I've looked at use the pre-2.6.20 workqueue interface. This includes the Linux Kernel Module Programming Guide, Robert Love's Linux Kernel Development, and Sreekrishnan Venkateswaran's Essential Linux Device Drivers which was published in April 2008!
Does anyone have a guide to using the "new" 2.6.20+ workqueue interface?
Just for reference, Ubuntu 8.04 which I'm developing on at the moment, was released over a year and a half ago and includes kernel 2.6.24.
Edit
stsquad's answer led me to this guide to porting code to the new 2.6.20 workqueue's.