"It's set to go off April 1, 2009 and Conficker will generate 50,000 URLS daily," says Don DeBolt, CA's director of threat research. Generating that many URLs is a way to hide where it may be calling to download instructions from those who designed it to infected machines. It's not known exactly what those instructions might be but it could involve downloading more malicious code or destroying files.
CA says it has some ideas about where originated but isn't discussing that at present.