Multi-value Fields - Appending / Updating with query
Access 2007 introduced Multi-value fields (MVF), some people like it, some – hate it. I personally like UI for MVF in Access, but don't like realization in table level – you can't get access to junction table of MVF. Anyway - any Access developer have to learn working with it, sooner or later, and here something your can look at.
A.D. Tejpal, Access MVP, has published Multi-value Fields - Query Based Solution For Bulk Appending / Updating sample database, which shows several techniques to work with MVF.