Remove everything from this directory, apart from 2 files:

/Library/Application Support/SyncService/501

(501 being by uid). The two files to keep are:


The latter was full of shite so I made it look like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "
<plist version="1.0">
                <string>00-0a-d9-e8-b7-3a</string>  <strong><---- change this to your mac address</strong>

Then try to repair the phone, it should find it and so does iSync.

Thanks to Steve for this fix