Well it's been a while but here is what I can think of.
Money: Bring lots of it. Really, bring as much money as you can. Any housing that you find will require damage deposit as well as advanced payment (like first and last month rent) Plus you might be there for a month or more before you get a paycheck. Bring at least a few thousand and you won't need to worry about it.
Work: All you can really do is find out when they have the job fair and show up. Don't bother sending a resume because they won't even look at you unless you are there. Try to find a job that interests you, you will be much happier. But if you are going to work in retail or food and beverage, try to get a job at the base of the mountain. If you are working on the mountain, you only work during ski hours and that means no 1/2 days of skiing. Also don't be afraid to take a job and then continue looking for a better job.
Housing: Housing in whistler is harder to find than a job, but one advantage you have is that Staff Residence gives priority to first year employees. I stayed in staff res and it wasn't too bad. You get a tiny apartment that you share with a couple other guys with a kitchen. There's not really much room for living space though. Basically you just sleep and eat there. But it's really close to the village. If you don't want to stay in staff res, show up a week or two before the job fair and look for an apartment.
Basically just pick a date and go. When you get there stay at a hostel until you find permanent housing. Also, in the summer and fall, they allow non staff to stay at residence until after the job fair. Expect to spend $10-15 a night (mabye more). Bring with you dress clothes, resume, references, cell phone (so potential landlords and employers can reach you). Leave your ski crap at home and ask your parents to UPS it to you when you have a perm. address.
That all I can say except GO you won't regret it.
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'Alcohol, Tobacco & Firearms should be the name of a store, not a government agency.'