SingleCase offers a quick overview of all unbilled timesheets. Invoicing is very fast, just filter the period you want to invoice. After that you just proceed as in the classic invoicing.
Open the "My Name"->Reports ->For Invoicing page, where you will find an overview of everything that is unbilled. Select the period in which you want to invoice, select the client or project/case and go to the invoicing by clicking the Enter Invoicing button on the client or project/file.
The statement will then appear in the second step of the invoicing process, where you continue as in traditional invoicing.