At the moment the bandwidth for each account on my server resets on the first of every month, how do I get it to reset a month after the account has been created, so if the account was created on the 10-01-2010 it should reset on the 10-02-2010.I am using cpanel/Whm.

Bandwidth is logged in /var/cpanel/bandwidth.cache and /var/cpanel/bandwidth. You might be able to write something that goes around those directories