Of course, there are other organizational implications of these systems. More important, the long-term use of ERP could change the broader organization in terms of its structure and function. It may be, for example, that there is less need for middle managers and that the organization can be a bit flatter. The post-ERP organization will need a different set of roles and skills than those with less integrated kinds of systems. At a minimum, everyone who uses these systems needs to be trained on how they work, how they relate to the business process and how a transaction ripples through the entire company whenever they press a key.
Most companies use consultants to help with the implementation process.
I'm hardly going to say this is a bad idea, as I get a monthly check from a consulting firm. If these systems will be around forever, it's important to have internal talent that knows as much as any consultant about how they work and how they can be configured to fit the organization. Make sure your consultants allow your people to work side by side with them on the implementation project, and before they leave tap the most knowledgeable consultants on long-term system evolution issues. In the early days after you turn the system on, these people will save your bacon. They'll answer questions, find needed work-arounds and let you know what's working and what isn't.