If you mean how do you configure a switch to pass traffic for more than one VLAN down a single cable then the answer is trunking.
Simply connect a 100BaseT or 100BaseFX cable from the switch to the router, configure this on the switch to be a trunk, configure this to be a trunk on the router (both using either ISL or 802.1q), then configure a seperate sub-interface for each VLAN on the router. The router will then pass traffic for each VLAN.
Let me know if you need any config help
Daniel,