Pd' Programming will be releasing a new version on Intersection Magic (probably with a different name). Once this version is complete, it will have direct support for ArcView 8.x.
In the meantime, we are working with ESRI to create a utility that will allow the existing IMW to communicate with the new ArcView 8.x. It should be available soon.
Until we release these two solutions, ESRI has documented that ArcView 3.x and 8.x can both exist on the same system without conflict. If you need to upgrade to 8, just leave 3 in place until we've completed our solutions.