Don't treat it like a big deal. The more you worry, the more your little one will. Casually mention to dp in dd's hearing that dd is getting a big bed because you know she is a big girl and not a baby any more- believe me, she'll want to prove you right!
ds was a bit iffy about the idea until I used a bed guard thingy which just gave him (and me) a bit of a sense of security against falling out accidentally. Think the 'not a big deal' approach has a lot going for it.
I'm a bit with Peachyclair - all my NCT friends fretted about it and I just didn't think about it as being a problem and luckily it wasn't. Moved ds1 when he was about 20 months as ds2 needed his cot! Moved ds2 this Jan and he was jus 2 cos we moved house and ds3 needed the cot!
Never had a problem really - they can get up a bit more really but if they are tired and normally good sleepers you'll probably find it fine!
Well DD had first night in her bed tonight!! Bless her. She looked so small in her new bed! ANyway, after an hour of pushing the boundries a bit (ie, realising she can actually escape now!!) she finally settled with relatively little fuss. Thanks for all your excellent advice ladies - i really appreiciate it XXX