First time, wild winter camping.... not the best combination, but don't be put off. God has a warped sense of humour and decided that he will bestow on me an uncontrolable urge to wild camp...and that he will make that urge be at its strongest in the middle of winter - so I too started my ventures during the wet and cold. My first was an absolute disaster (see the thread elsewhere on the forum) and resulted in me chasing my (erected) tent across the boggy moors at 4 in the morning when the wind decided to pick it up and take it for a flight.
What got me down more than anything over those two days (yes, two) was the cold and wet. Granted I had a shit tent back then (little more than a garden tent) and was hopping around inside trying to avoid the four inch pools of rain water. I've never been happier to see my own bed back at home.
So the only advice I can really offer for winter camping is that you make sure you have a tent that you know will keep out the hardest and most persistent of rain. A high spec sleeping bag and good mat will also be essential. As for provisions, I find that anything dried, which can simply be cooked in boiling water is perfect (packets of flavoured pasta or rice). Other good foods: Beef jerky, cereal bars, chocolate bars, nuts, seeds. For cooking (unless you intend to use open fires) I cannot reccommend the Mini Trangia enough (£20-ish) . This little beauty is absolutley storm proof and will boil a pan full of water in about 3 minutes.
Having said all that, Ray Mears reckons you can survive sub-zero tempertures with a good fire and a shelter made from materials provided by nature herself.
I envy your trip. Good luck.
Edited: 22/08/2008 at 01:35