If you are trying to download the Cisco VPN client 4.x or 5.x then prepare for the bad news. You can’t. Not unless you are a registered customer that is.
Where can I download the Cisco VPN Client software?
A. You must log in and possess a valid service contract in order to access the Cisco VPN Client software. Cisco VPN Client software can be downloaded from the Cisco Download Software ( registered customers only) page. If you do not have a valid service contract associated with your Cisco.com profile, you cannot log in and download the VPN client software.
In order to obtain a valid service contract, you can:
See the Cisco VPN Client FAQs for further information.