Yes, of course. You can update to an image that support IPSEC. This will give you a relatively slow throughput, so I suggest you purchase their AIM-VPM/BP encryption acceleration card that will bring your IPSEC throughput back up to respectible lev...
I would reccomend using the new Cisco VPN client v3.0. You will require PIX v6.0, but this is a must improved VPN Client. In the future, we will be migrating exclusively to this new VPN Client for all of our VPN platforms.