Yes, you heard me. Free as in “no charge.”
Over the course of two years, BBC-produced Wildlife Magazine published a 12-part series on photographing the locations and creatures of nature written by talented photographers and including spectacular images. Until now, you would've had to find the 12 specific issues of Wildlife in order to read these tips, and for the effort it probably wouldn't have been worth it. I, for one, am a lazy person, having grown up in the age of the Internet where any and all useful information is a click away, so rummaging through magazine back-issues is right out.
Fortunately for people like me, Wildlife has released all 12 “Photo Masterclass” articles in PDF format on their website for free download. Regrettably, the PDF files are print-restricted, so you can only view them on a computer. If you have GoodReader.html on your iPhone or iPod Touch, however, you can take these lessons with you wherever you go. (GoodReader is how I take every single Canon and Nikon DSLR manual with me on my workshops I'll write more about that later on).
To view and download all of the Photo Masterclass articles, visit the Photo Masterclass page on BBC Wildlife
[Edit: It appears that they have taken down articles 11 and 12; they no longer appear on the site. Unfortunately I don't have local copies of the articles to share with everyone, so they may be lost forever.]