11. A handheld computer for facilitating search and retrieval of a personal information manager data item associated with a personal information manager application executing on said handheld computer, said handheld computer adapted to: consequent upon associating a given personal information manager data item with said personal information manager application: derive a keyword pattern from a given keyword of said given data item in accordance with a first mapping function; associate said keyword pattern with said given data item, said keyword pattern being an ordered plurality of elements; receive a selection for a category for said given data item and associate a category pattern with said given data item, said category pattern being a second ordered plurality of elements, said category pattern derived in accordance with a second mapping function different from said first mapping function such that no keyword search string maps to said category pattern; consequent upon receiving a user search request comprising an entered keyword search string or an indication of a category to be searched: generate a target pattern from said user search request; search personal information manager data items associated with said personal information manager application to identify personal information manager data items matching said target pattern, said search comprising: for each particular personal information manager data item encountered, comparing said target pattern with each category pattern and each keyword pattern associated with said particular personal information manager data item so that a single search on any given target pattern covers category patterns and keyword patterns associated with personal information manager data items; returning each personal information manager data item having an associated category pattern or associated keyword pattern which matches said target pattern.
11. A handheld computer for facilitating search and retrieval of a personal information manager data item associated with a personal information manager application executing on said handheld computer, said handheld computer adapted to: consequent upon associating a given personal information manager data item with said personal information manager application: derive a keyword pattern from a given keyword of said given data item in accordance with a first mapping function; associate said keyword pattern with said given data item, said keyword pattern being an ordered plurality of elements; receive a selection for a category for said given data item and associate a category pattern with said given data item, said category pattern being a second ordered plurality of elements, said category pattern derived in accordance with a second mapping function different from said first mapping function such that no keyword search string maps to said category pattern; consequent upon receiving a user search request comprising an entered keyword search string or an indication of a category to be searched: generate a target pattern from said user search request; search personal information manager data items associated with said personal information manager application to identify personal information manager data items matching said target pattern, said search comprising: for each particular personal information manager data item encountered, comparing said target pattern with each category pattern and each keyword pattern associated with said particular personal information manager data item so that a single search on any given target pattern covers category patterns and keyword patterns associated with personal information manager data items; returning each personal information manager data item having an associated category pattern or associated keyword pattern which matches said target pattern. 13. The handheld computer of claim 11 wherein said receive a selection for a category comprises receiving a selection from a master list of categories and wherein said handheld computer is further adapted to: add a category to said master list of categories; receive a new category name; associate a plurality of elements with said new category name, said plurality of elements being derived in accordance with said second mapping function; and add a reference to said new category name to said master list of categories.