How do I rescue SQL Agent jobs from a set of detached master, model, mdb files?
You will have to attach the MSDB DB under a different name like 'jobsdb' and pull the jobs out of jobsdb. The jobs will be stored under jobsdb.dbo.sysjobs and the job steps will be under jobsdb.dbo.sysjobsteps. They can be joined by the job_id column.

The schedules can be found under jobsdb.dbo.sysjobschedules joined with jobsdb.dbo.sysschedules on schedule_id.

The rows can be added into your current msdb using a insert-select, or by using the stored procedures: sp_add_job, sp_add_jobstep, sp_add_jobschedule, sp_add_jobserver.