In reply to tattoo2005: Well the actual business of using axes/crampons is very simple although, as you get onto more technical mixed ground on the harder routes, the repertoire of skills/techniques increases. Placing rock pro is the same although placements can be more difficult to find(buried under snow/rime), screws and the more "exotic protection don't take much to master. And belaying etc is essentially the same.
The additional things for winter are navigation, especially in sh*t conditions, efficiency with kit and a tolerance to a bit of discomfort is useful!
IMO winter climbing is the most rewarding/addictive and bloody frustrating time you can spend in the hills!
You've just got to give it a go.
Iain