Canal House Cooking, which publishes some excellent periodical cookbooks, first published a preserved lemon recipe in their book "Canal House Cooking Volume 1" along with many recipes and suggestions for using them (they go far and beyond just tagines!). Here is a blog post of their recipe http://blog.thecanalhouse.com/2010/05/lunch-for-the-creative-crew-from-williams%E2%80%93sonoma/.

Be sure to check out their cookbooks, too!

I love a good Moroccan-styled Preserved Lemons, and so simple to make!
(based on a recipe from Chow.com)
1) Wash your lemons thoroughly to get whatever waxes and pesticides off - I use a veggie soak, but I hear a drop of detergent works well too.
2) Slice your lemons, length-wise, into eights WITHOUT slicing through one end, so it opens up like a flower. Rub a handful of Kosher salt into the lemon, making sure it covers all the nooks and crannies, and stuff it into a mason jar. Fit as many lemons as you can into your jar.This, of course, depends on how big your jar (and lemons) is .
3) Fill said jar about 1/2 way with freshly squeezed lemon juice, then fill it up with salt. Put your lid onto the jar, and put the whole thing into the fridge. Give it a shake every day and your lemons will be ready in about a month.

Mark Bittman's recipe (from The New York Times) for quick preserved lemons is in this thread:
http://food52.com/hotline/18644-how-to-make-preserved-lemons

Here's a very simple/basic recipe
http://www.marthastewart.com/866636/preserved-lemons