Encrypted VPN in Linux via Ethernet/Cable Modem?

[jmills]

At work, we have just implemented VPN via our cisco firewall which requires Windows machines to run a VPN client with an access key configured to connect to our newly encrypted servers from the internet.
I use a Citrix Metaframe ICA Linux Client to connect to these servers via an ethernet card and cable modem on my Linux machine, or at least used to.
Since the data is now encrypted and a key is required, I can obviously no longer connect to the servers.
Is there a Linux solution for this?
I had a quick look at the PPTP client for Linux (

http://cag.lcs.mit.edu/~cananian/Projects/PPTP/),

but it seemed to be aimed towards PPPD connections, not ethernet.
Can anyone point me in the right direction?