Slight rewrite of http://www.sqlservercentral.com/Forums/Topic1733134-3077-1.aspx
--declare @JobName sysname ='Your Job Name'
SELECT *
FROM msdb.dbo.sysjobs_view j
JOIN msdb.dbo.sysjobactivity a
ON (j.job_id = a.job_id)
JOIN (SELECT MAX(session_id) AS session_id FROM msdb.dbo.syssessions) s
ON s.session_id = a.session_id
WHERE j.enabled = 1
AND a.run_requested_date IS NOT NULL
AND a.stop_execution_date IS NULL
--AND j.name = @JobName