Well, it really all depends on what exactly you want to do.
Biztalk can integration with SAP through the SAP Adapter. That will be included with Biztalk 2006. Also, integration with SQL is built in through the SQL Adapter.
So, it would really be a matter of getting the data out of SAP via the adapter, mapping it, and putting it into SQL.
I do not know of an Excel Adapter. You might have to export the data as a csv or something Excel can import.
Hope this helps.