Bootcamp says "insert windows 7 install disk" When my bootcamp asks me to inset windows 7 install disk, do I need to purchase a physical install disk or do I need to just purchase a windows 7 copy online with a product key?

My Mac's Model is: MacBook Pro: (13-inch, Mid 2010) Processor: 2.66 GHz Intel Core 2 Duo Memory: 4 GB 1067 MHz DDR3 Graphics: NVIDIA GeForce 320M 256 MB
No, there's no need to buy a physical install disk. You can certainly purchase Windows 7 online to get a product key. The ISO file containing Windows 7 can be downloaded from Microsofts web site, allowing you to install via BootCamp.