>>Is there no way to roll a db back from 2008 to 2000?<<
I'm afraid not. What you can do though is recreate the database in SQL 2000:
1. Create new database in SQL 2000
2. Generate scripts from objects on the SQL 2008
3. Execute this scripts on the SQL 2000
This is considering that the SQL 2008 DB objects are all compatible with SQL 2000.