Week two in the reanimation of the Tutorial of the Week sees this as a highlight: A great rundown on How To: Use GnuPG along with WHIRLPOOL Hash to Encrypt an Individual File.
True, this thread is a little dated, but presentation and style are what counts here, and of course the issue of encryption is certainly no less pertinent.
kevdog, a forum regular, has put together a narrative that is easy to read and which explains many of the principles for beginners or less experienced users.
And as an added bonus, there is a long list of examples that show the commands and codes in action. Finally, with plenty of external links, it does a good job giving you extra information in case you want to investigate further.
And so for giving us the Tutorial of the Week for Feb. 17, 2011 ... a gold star for kevdog: