You can backorder it if it's set to expire soon (I've done that with GoDaddy - they lock you in for 90 days after you use their service to register).

You can use a service like afternic's assisted offers: http://www.afternic.com/uoffer.php

or you can TM the name and see if a lawyer's letter will convince them that they should hand over the domain, although that's sort of evil and it didn't work out well for Nissan (http://www.nissan.com).

Or yeah, contact the owner directly, that's an easy way to figure out if they're interested, although any interest immediately makes the psychological value of the domain go way up for the owner.