You could use pre defined VPN profiles for this. If you are using Cisco VPN client and currently using a profile on it you should be able to see a file with extension .pcf and any one can import this configuration to VPN clinet software. Usually the .pcf file will be available at
C:\Programs files\Cisco Systems\VPN Client\Profiles
You could upload the VPN client software and profile on to one of your sharepoint server and could ask users to download using the path provided by writing them an email.
Also it would be more easy for users if you could make a 1 or 2 page document and send this as a email attachment which explains the procedure for VPN client software download and profile import.
Hope this helps.