If Senator Stevens is expelled or if he resigns after the new Senate session begins, what happens next? There's a bit of a dispute over which rules apply. The old rules (see here) provided for the governor to fill a vacancy and then to call a special election afterwards, if the term would expire in more than 30 months. A controversy over the last Alaskan governor appointing his daughter to a vacant Senate seat led Alaska voters to pass an initiative changing the law. Under the new law, the governor still may appoint a temporary person to the seat, who sits only until a special election is called in 60-90 days after the vacancy occurs. Because Senator Stevens' term would expire in more than 30 months, there's not much difference between these old and new laws, except as to the timing of the special election.
There's a constitutional question under the 17th Amendment whether an initiated change to the means for filling Senate vacancies are constitutional. Vik Amar thinks it is. I'm not so sure (I address a similar, but not identical, issue in this paper).
So, either way, the governor will have the power to fill a vacancy at least for the short time (meaning this Washington Wire post is incorrect at the end). The difference might only be in the timing of the special election.
Anyway, subject to additional complications I haven't thought of, that's likely how things would go: expulsion, temporary appointment, special election.
So even if Stevens wins, he's not likely to enjoy his laurels for long and Democrats could be looking to take the seat in short order anyway.