All of my remote contractors invoice me weekly. We just use a shared google spreadsheet that track times on one tab and sums it on another by week. I actually

All of my remote contractors invoice me weekly. We just use a shared google spreadsheet that track times on one tab and sums it on another by week. I actually handle payments via xoom.com -- it is now owned by paypal. It takes a little work to setup a new payee, but once you have paid a person once, you can pay them again very easily.