Sales Commissions - Need Help

We need to calculate commissions by 1/31/08 and at this point, I am
unsure how best to go about this. We went live October of 2007 and
have been working hard at understanding the system.

We pay invoices by the net profit for paid invoices. We pay inside
sales people for writing up sales orders and we pay outside
salespeople for sales to their predetermined customers, no matter who
writes up the order.

Is there any report writers or someone that can guide me as to how I
can go about writing such a report, or exporting out to a spreadsheet?

We have never paid salespeople on Vantage invoices yet. This is
something completely new to us.

We pay commission also per line item, we would like to see the item
that was sold, it's cost, profit, and if the invoice was paid or not.

Again, any help would be deeply appreciated.

Thanks,
Toby