I've always oven dried mine, spread in one layer over baking trays at about gas mark 1/4 for around 6 hours or untill dry and crispy. But recently ive been looking at other ways as its not very cost effective.
You can dry small amounts of leaves in the microwave in 30 second blasts untill dry but again its not cheap electric wise and if you let them dry to much they could catch fire which is never good.
Ive tried sundrying them in seed planting trays on the balcony but you have to stop them blowing away especially in the windy weather were having at the moment i just use the lids that come with the trays (4 for a pound at poundland) and it makes like a mini greenhouse.
I have some bunched and tied with string and pegged to my washing line at the moment but i havnt got a verdict on that method yet as theyve only just gone out there
jen