I noticed you can use the following stored procedures (in order) to schedule a SSIS package:

msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'[Uncategorized (Local)]'
msdb.dbo.sp_add_job ...
msdb.dbo.sp_add_jobstep ...
msdb.dbo.sp_update_job ...
msdb.dbo.sp_add_jobschedule ...
msdb.dbo.sp_add_jobserver ...

(You can see an example by right clicking a scheduled job and selecting "Script Job as-> Create To".)

AND you can use sp_start_job to execute the job immediately, effectively running SSIS packages on demand.

Question: does anyone know of any msdb.dbo.[...] stored procedures that simply allow you to run SSIS packages on the fly without using sp_cmdshell directly, or some easier approach?