I have a Network Dataset layer that I use to perform routing. Even if a starting or ending point is not near a road in the Network Dataset layer, I still want to perform routing using those points. Is there a way that I can get the routing to start at the nearest place on the ND, to the starting point, or end on the route at the closest place near the ending point?
ArcMap should do this for you automatically (snap off-network points to the nearest spot on the network) when you load locations into your analysis layer using the Network Analyst toolbar. If you need more control over which classes get locations snapped to them, you can do this in the "Layer Properties" window of your network analysis layer. See "Search tolerance and snapping environment" on this page:
If I understand your question right, you have the Network Analyst extension, you should be able to snap your origin/destination points to the network automatically. If you look under the Network Analyst Options there are Location Snap Options. There is more information in this help page: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00470000003n000000
Hope that helps, David