Not sure why a "Free" service like iCloud would not be helpful
Using Dropbox is workable for both platforms. iCloud will not be very helpful if you're running a different system. iCloud will only be available to the Mac unless he upgrades to Lion. A parking lot system using QR code and the right iSO app would be interesting . iCloud it to far off for everyone to take advantage of. The fact thats is free, will give you the opportunity to see if you can use it or not.
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