This week's book giveaway is in the Agile and other Processes forum. We're giving away four copies of The Mikado Method and have Ola Ellnestam and Daniel Brolund on-line! See this thread for details.
In my humble opinion, integration testing is testing the changed or new application with it's immediate system neighbours e.g. if you had a new barcode scanning device in a warehouse system, then integration testing might be testing it against whatever sends data to it and whatever receives it's data. System testing would be testing the whole chain of events that included the barcode reader e.g. The entire ordering, warehousing and dispatch operations.