Graduates of Ph.D. Programs in Planning seek a wide range of careers from academic positions at unversities and colleges, to private consulting and government policy work. Regardless of the career path you intend to pursue networking during the course of your studies is an effective way to have access to jobs as they become available. Attendance and participation at academic and professional conferences is an important way to meet people in your field of interest.
Below are links to academic and professional sites that might be of interest.
Association of Collegiate Schools of Planning - ACSP Jobs Page (academic positions)
Canadian Institute of Planners - CIP job board (also has good links to other resources)