Shawn took issue with this, responding:
it isn't uncommon for me to be at my desk between phone screens or meetings, talking with a coworker, or just plain busy, and to just let a call go to voice mail. we are a non-profit but can afford phones with caller id. i've had candidates call every 15 minutes. it's obvious when the same number keeps calling. this looks extremely needy, besides flat out annoying me.
find an email address and use it.
I agree wholeheartedly with Shawn. Most people have Caller ID these days. I frequently let calls go to voicemail when I'm in the midst of something else and not at a good stopping point, and I've seen candidates call over and over without leaving a message. You may think you're being strategic, but if the person is sitting right there, it's annoying. And you look a little stalker-ish.
I used to have a coworker who bragged about using this technique (not in a job-searching context; in a business context). He seemed to think he was being crafty, but in reality I'm sure he was annoying the crap out of the person sitting there seeing his number pop up over and over again.
Leave a message. And like Shawn says, email is better.