I've been sitting looking at my new pedals (shimano PD-M875) and my new shoes (Mavic Pulse) for about 10 days. I wanted good weather and enough time to practice so today was the day!
I did 21 miles (still a decent distance for a recovering fatty like me) without a hitch. I did forget I was clipped in a couple of times as I approached junctions etc but got lucky.
I read all the advice on here and without doubt it made the transition far less daunting. One piece I especially liked was the piece about setting the pedals to their weakest setting (I can't recall who offered this advice though they deserve a mention). There was a little movement because of this setting but the fact that I was able to escape if needed boosted my confidence.
Thanks to everyone who has contributed to this thread, you've all helped me.
My only advice to anyone thinking of going clipless is, read this thread thoroughly before you do and I doubt you'll go far wrong.
Don't worry, I don't think for one minute I've cracked it, I fully expect a good few "clipless moments"