I don't know anything about enterprise resource planning (ERP) products, except that SAP are a big player in this space (and that Microsoft runs its business on SAP with a 1.7Tb SQL Server database - pretty much the only non-Microsoft product in use there). Last night,
Mat Stephen mentioned the
Microsoft/SAP Alliance website and, after having taken a look this morning,
the technology section (including details of how to integrate SAP and Microsoft products) looks pretty useful to me.