This script writes a Certification Authority’s Certificate Revocation List to HTTP based CRL Distribution Points via a UNC path. It checks to make sure that the copy was successful and that the CDPs have not and are not about to expire. Alerts/status messages are sent via SMTP and eventlog entries.

http://blogs.technet.com/b/pki/archive/2010/05/12/powershell-crl-copy.aspx