I emailed TomTom about whether Navigator 6 works on the i8510 and they sent me what looks like a stock reply:
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Please go to the below links to view the devices that are currently supported for use with Navigator 6.
http://www.tomtom.com/products/features.php?ID=286&Category=2&Lid=4http://www.tomtom.com/products/features.php?ID=260&Category=2&Lid=1Your PDA is not supported for use with Navigator 6.
At TomTom we aim to test as many PDA's and Mobile Phones with our Navigator Products. However not all PDA's and Phones are compatible with our products due to the hardware restraints of the device, or the ROM version installed on the device.
As more and more PDA's, Phones and other handheld devices become available on the market, it is not always possible to test all devices straight away. When we find that a device performs well with our products, we will list the device as compatible on our website.
Our Compatibility lists are updated as regularly as possible, but you find that your device is not listed in the compatibility lists above, then your device has been deemed incompatible.
It is TomTom's policy not to support incompatible devices with our products. We only suggest installing our products onto compatible PDA's, Phones and other Handheld devices.
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That's a shame as most people on various web sites seem to think TomTom is better than Route66. The i8510 has only just come out though, so it could just be that they haven't tested it yet.