Cash versus accruer accounting

[marc at osmium.mv.net]

Hi -

I use gnucash for my small business bookkeeping. I use the business features. 
For US tax purposes, I operate on a cash basis.

When I create an invoice, I associate the line items on the invoice against an 
income account. The accounts receivable which invoices are posted to, and an 
asset account.

When I run reports, such as profit & loss, I end up seeing data not based on 
cash (e.g. when payment is actually received), but instead based on accruer 
(e.g. when the invoice is initially posted).

What I would like to do is to change my method of using the system so that the 
reports show a cash basis. So, my question is, how is that best achieved?

Thanks in advance - Marc