DNS Problem

Active directory has just been inplemented on our network. The DNS are allocated via DHCP and all is working fine. The problem occures when users with laptops connect to their home broadband and there is no connection to the internet, as the laptop is holding the work DNS numbers, how can i get round this to make the laptops connect to the internet. I have tried flushing DNS to no avail.

OS on all laptops is XP.

Many thanks

Nick