OpenVPN can't be used to connect as a client to a Cisco VPN concentrator. For that you need the vpnc client. Also available in HAM.
Maybe only in extras-devel, I have extras-devel enabled from day one and never looked back.

For specifics on how to configure vpnc, use google search.

Have a look here. It seems easy enough : http://www.debuntu.org/how-to-connec...vpn-using-vpnc

Have fun.