Propilot is on the mark, here. Being there is worth more than experience sometimes. Most Anchorage based companies are hiring a little all year round, but seem to have a bigger push for the summer gear-up. That happens about April-May. Everyone seems to have NFG ground school going then. Walking around, shaking hands and passing out resume's will work much better than sitting at home sending emails. That's for the 135 outfits. Move up to the 121 operators, and they seem to be hiring more steadily. Hiring on as an f/o for your first AK season may not be a bad idea if you're short on stick and rudder/mountainous/dynamic weather experience.
That being said, I hired on to a tundra/bush operator over the phone. Came up to work one season... 3 seasons ago. Took a break and played captain in the regionals, then came back. I prefer a little mud on my boots than gold on my shoulder boards!
Good luck,
Ronin