Can I use a Rogers phone with a Virgin Mobile plan?

[Plays with squirrels.]

I purchased a Rogers phone--HTC Magic--and I bought the phone itself, I don't have a plan. It's on a pay as you go plan, and I don't like the pay as you go plans with Rogers and I want to switch to Virgin Mobile. Is it possible to "unlock" the Rogers phone and use it with a Virgin Mobile pay as you go plan? I don't really know how it works.

Thanks.