Add-ins are VBA-based & there is no VBA support in Office 2008, hence no
add-ins. However, the add-ins essentially just facilitate doing what can
still be done in the program if you know how. And there have been some tools
suggested by others that may help you out if you can be more specific about
what it is that you're looking for.
Regards |:>)
Bob Jones
[MVP] Office:Mac