It is sometimes hard to find Cisco VPN Clients for download. Below is a place that seems to have current and old downloads at the moment:
Click for current downloads.
Click for old downloads.
I haven’t tried it myself, but I see some people have used another VPN client as well. I believe this was perhaps in use before Cisco supported Win 7 64-bit, but here is the link none-the-less: http://shrew.net/download