I'm going to be taking my A1 on a ski trip/documentary. I am new to housing and protection for the camera. What do i need? Just a water-proofing bag, full housing, different microphones? Can you recommend products as well? Thanks.

The answer depends upon what might happen to it. If you're just going to take it out to where it might be snowing then I would recommend this:
http://www.bhphotovideo.com/c/product/475695-REG/Porta_Brace_RS_XHAG1_RS_XHAG1_Mini_DV_Rain_Slicker.html

I have one of these and have used it in the snow for a few months with good results. It protects quite well and one neat feature is that there's a sealable opening on the top that you can see in the picture that will allow you to slip your hand inside to grab the top handle. The fabric in the opening will seal around your arm. Access is good while shooting and when not shooting it will seal up pretty tight against the elements.

If you're going to shoot where it's near 0 degrees F, you might think about a warming bag. If you're above 20 degrees F, the rain slicker will do fine.

If you're going to do any interviews, get a good shotgun mic. The Rode models get good notices for inexpensive units and I've had good luck with mine. Step up in price and Sennheiser is one of several good options.

If you're just going to capture ambient sound, you can get away with the onboard mic, but they won't be any good for anything else.

If you don't have a case, you might want to look into a bag. I have a Petrol and like it. For hard cases it's hard to beat Pelican.

Hope that helps. Have fun.

Keep in mind that your batteries wont last as long in the cold temps.

Keep in mind that your batteries wont last as long in the cold temps.

Good point. I have one of the large capacity batteries made by Impact and in all of the near and sub-freezing shooting I've done I've never run out of juice. I don't think I've ever actually used the Canon battery yet.