We are at the time in the academic job market cycle when some ABDs and new PhDs will begin considering visiting professor positions.
I have heard some of my colleagues discourage students from applying. But I think that is the wrong advice for most new PhDs (and ABDs that are truly going to defend prior to fall 2011).
My first academic job was as a visiting professor. I was on the market but still ABD and hadn't gotten any interviews. None. But then I saw a flier at a regional conference in spring about a visiting position. I interviewed for it at the conference and got the job.
This job was awesome. It was in a smallish dept at a small liberal arts college. My colleagues were great. We had a lot of fun together. And they were supportive of my research and ongoing job search. Plus, when a new professor line opened up a year later, guess who they immediately contacted? Me! I was about to accept a great TT job elsewhere, so I didn't apply. But I think I would have had a definite advantage in that job search.
To be clear, I think job searches should be truly competitive. But when a popular visiting professor is competing for a tenure-track job, in my experience the search is NOT as competitive as it should be. On the hiring end, it has been pretty clear. I have been on search committees and heard colleagues argue that we "should" give visiting professor "Bob" an interview for the tenure-track position. This even though we just hired "Bob" at the last minute as a visiting professor in a very uncompetitive process when some money came available and he was in the right place at the right time. And even though his CV was in not competitive with the other top CVs we were considering. And even though he hadn't been all that great in the classroom! (We didn't interview "Bob," but I had to be the big meanie arguing the case against him.)
Right or wrong, faculty often feel obligated to a visiting professor. Or they become friends. This can be a definite advantage in moving from visiting to tenure track at that institution.
I've lost several jobs to the inside candidate. It looks like one of my grad students just lost a job to the inside candidate. This isn't to say that the jobs would have been ours but for the visiting professor. But it is to say that it was the visiting professor who was hired.
Visiting professor positions also help us widen our career networks. I've gotten a few opportunities thrown my way from my old colleagues, plus some lasting friendships. Plus, it doesn't look bad on the CV--at least I've never heard a negative comment on it.
Surely there are down-sides to the visiting professor job. I can see how a visiting professor might feel ignored, underpaid, disrespected. But you won't know if it is THAT kind of situation until you're there.
And hey, it is a job!