Its not in the system manager menu anymore.
It has been removed in favor of the new Universal Device Poller.
Go to Start-->Programs--> Solarwinds Orion-->Universal Device Poller.
Note that the UnDP is fully backward compatible with pollers created by the CMP.
Yes, that is important to remember. You can also import custom pollers just like you could with the CMP (including those in the Thwack content sharing zone)
Thanks for the info guys. I just started messing with the custom stuff here so I don't have anything to import.
One other thing you might consider. If you don't already have the SW Engineers Toolset, you should try it out. There are some SNMP MIB tools that would be invaluable in helping you gather custom OID data from devices on your network that Orion may not monitor out of the box.