The following Powershell functions allow you to manage querying, creating and removing scheduled tasks on one or more computers remotely.
The functions use schtasks.exe, which is included in Windows. Unlike the Win32_ScheduledJob WMI class, the schtasks.exe commandline tool will show manually created tasks, as well as script-created ones. The examples show some, but not all parameters in action. I think the parameter names are descriptive enough to figure it out, really. If not, take a look at schtasks.exe /?. One tip: try piping a list of computer names to foreach-object and into this function.