A blogger for security firm Sophos has issued a writeup about the new worm, indicating among other things it may be attempting to pilfer sensitive information from people's phones. As the worm compromises the phone in its entirety, any information the device has access to could -- in theory -- be transmitted outside. A more noticeable effect will be the loss of battery life, with reports that an infected phone will have a seriously reduced runtime.
Thankfully, Sophos has posted an easy fix: return your firmware to the latest Apple-released official version. While that's not what jailbreakers want to hear, at least it's an option. This also serves as a warning to people who modify their devices; make sure you are taking the extra steps needed to secure yourself.