>I'm wondering what the general concensus is
>for invoicing clients.
>
>Do I use a standard invoice with line items for
>each task, with a total at the bottom? Or should
>I use some other format?

Why not use QuickBooks? It has a timer so you can track actual time spent on each project. I use it to break up a project into tasks and then each task becomes a line item on the invoice.