OOF, that sucks. I am sure most of us have had similar events happen. I know I have!
First things first, go on eBay and get two things. Get a repair manual on CD-ROM. It will give you everything you need to know, torques and blow-up parts diagrams. If you can wrench, you can use that to solve all your problems. Next, find that trailing arm. You can get em for good prices most of the time but if your bud can get them for cheap you may already have that covered.
Although I don't know of any tech articles for you, I can tell you that the bend looks good and isolated to just the trailing arm. That is, it doesn't look like much of the force transferred to the tunnel by the looks of that arm. Be certain to check the tunnel by standing behind the sled and looking lengthwise down the right floorboard, both from the top and underside. Also look the entire sled over for signs of stress transfer to the frame/tunnel. Again, looks like that arm took the punch cleanly in the face and that's a good thing. And check all the tie rod and steering arms for straightness.
I had a close encounter with a driveway drain culvert that flipped me over the hood and bent a trailing arm similar to yours. I fixed it in 1 hours when I got the parts from Ronnies!
http://216.37.204.202/Skidoo_OEM/Skidoo.asp
With parts in hand, this is an easy fix so stay cool and don't worry too much.
Ed
I know the trailing arm needs to be replaced and maybe the tierod, but I'm not sure what else. Here is a pic of what happened (right side of sled):
Linear Mode
