SharePoint Cross-Site Lookup Pack contains two powerful lookup enhancements: SharePoint Cross-Site Lookup and SharePoint Cascaded Lookup. Designed to fully complement each other, these two enhancements offer a suite of features that dramatically leverage your SharePoint lookup functionality.
Cross-Site Lookup allows you to look up and pull information from any site in a site collection, adds find-as-you-type functionality to your lookup field, and filters items displayed in the lookup field according to a view defined in the source list (the list where the information is being looked up from).
Cascaded Lookup also allows you to look up and pull information from any site in a site collection and reduce the number of options presented in a lookup field by using a series of related filters. Building parent-child relationships between columns in the same list so that data entered in one field will filter the options presented in another.