hi you can do this by using
ddl1.DataSource = some dataSource;
ddl1.DataTextField = "table column name";
ddl1.DataValueField = "table column name";
ddl1.DataBind();
DataTextField will be the text that will be displayed in dropdown and DataValueField will be the value feild that corresponds to text. both may contain same column as well it depends what information you want to retreive and display.
if you want to retreive differebt feild when some item is selected in dropdown then bind different columns to dropdown
thanks i hope that this may help.