Preserving lemons is absurdly easy. All you need is lemons, salt and a jam jar. My main difficulty with preserved lemons was that I never quite knew what to do with them. Who needs all that salty lemon? Fortunately it turns out that they last for ages (mine have gone a year in the fridge although the liquid they're in starts to look a bit scary), you only use the rind anyhow, and they make a delicious addition to cous cous. Anything which makes cous cous taste of something gets my vote (add some raisins while you're at it, and toasted pine nuts if you're in the mood for actual cooking). You can add them to rice or salad or even make a traditional tagine. To be honest I've never made a traditional tagine (one of these days...) but if I did I'm certain I'd need a preserved lemon.
Anyway, make them: it's fun. Quarter the lemons without cutting them all the way through, pack them with salt and stuff them into a clean jam jar. I've discovered that a tight squeeze works better, and there's always the comedy value of lemon juice squirting in your eye as you force them in. Stuff in a bit more salt, add a bay leaf and some coriander seed if you feel fancy, then screw on the lid and leave for about three days. The juice theoretically comes out of the lemons and fills up the jar, but when it doesn't you can top up the jar from the tap. Shove them in the back of the fridge and after a month you can have fun hoiking them out and slicing off bits. Cous cous that actually tastes of something. Who knew?