The first one is called Taterf which has infected over 1.2 milion machines worldwide during its first week. The other worm is called Frethog and has so far a 650,000+ machine first-week infection rate. These rates are stunning to malware specialists who are used to seeing these kinds of numbers only after a month of the worm's existance. These worms take advantage of Windows' autoplay and autorun functions that run for CDs, DVDs, and some USB sticks. They can be sneaky about it too. They try to disquise autorun with other pop-up dialog boxes, like "Show me these awesome pictures." You do need to confirm this action manually, but this obstacle hasn't much limited the spread of the worms to date.
Make sure you read the instructions on Microsoft's support site for how to protect yourself from these worms. The short answer is to disable autorun from CDs under XP (a registry change) or to change the same option from the Vista control panel. You should also disable autoplay as an even greater precaution. Also, of course, make sure you check the box on the WoW login screen to save your account name. That way if you do get infected with a keylogger, they won't be able to see your keystrokes for both your account name and your password.