According to sources, Canadian carrier Rogers had begun to roll out the OTA Jelly Bean update for the HTC One X earlier today. Since the size of this update is more than 634 MB, it is advisable for you to connect your device to the WiFi before initializing the update for your device.
However if you have yet to receive the OTA update on your device, you can go to Settings > About phone > System software updates to manually scan for your Jelly Bean update just in case you’ve been missed out. So have you updated your HTC One X?