I’ve just listened to a very interesting blog on Notes to SharePoint migration from Quest.
If there is anyway thinking about migrating away from Notes then it is well worth considering. It was pitched more on migrating to SharePoint 2010 but I know Quest do tools for SharePoint 2007 as well.
A blog post about it is here: http://notes2sharepoint.org/archive/2009/11/30/web-event-10-ways-sharepoint-2010-will-impact-your-lotus-notes-migration.aspx but I am sure it will be archived and viewable on-demand soon.