One of our favorite services for keyword research is WordTracker and they have come out with a new e-book — all 75 pages packed with tips and techniques for doing keyword research. Contributors to the ebook include Bryan Eisenberg, BL Ochman, Kevin Lee and Nick Usborne.
Download the keyword research guide here.
SIGN UP FOR EXCLUSIVE WEEKLY CONTENT 
Great tip! I’ve checked the guide and is really interesting. Would you have other suggestions on web marketing guides that don’t necessarily rely on paid marketing tools?
Anna
FYI the link has been moved – the new location for direct download is:
http://www.wordtracker.com/attachments/keyword-research-guide.pdf
Just found your post while doing some keyword research. After having gotten a proposal from you way back at Homestead (years ago), I remember that you know your stuff. Going to add you to my RSS reader now!