Note: This topic was updated for 9.3.1.
The Simple Data Loader wizard in ArcCatalog allows you to specify a number of source tables and feature classes, provided their schemas match. It also allows you to specify which fields in the input data are loaded into which fields of the target feature class or table.
The wizard also gives you the option of loading all the source data into a subtype of the target and lets you specify a query to limit the features you load.