Joel Spolsky mentioned that he is using the full-text search feature of SQL Server and that it required a manual job to re-index the database.
In fact, SQL Server 2000 will monitor a table for changes to a table that is included in a full-text index. The sp_fulltext_table procedure has parameters to 'Start_change_tracking' and 'Start_background_updateindex'.
As I wrote in Joel's discussion board, I have a script I could share that enumerates all indexes on a server and sets the change tracking for all tables in the index.