This is a big deal folks. There was lots of speculation and no real definitive word as to whether Cisco's VPN client will or would work with 10.5.
Well, I can tell you right now that I installed 4.9.01 right after my (clean) install of Leopard, and it works great. If you don't want to have to configure it once you've installed it, make a backup copy of the configuration folders, and then you'll be all set to overwrite the new installation's default folders.
Read on for how to copy your 10.4.x Cisco VPN configs over to 10.5.x Cisco VPN.
On a 10.4 box, in a Terminal window, do the following:
$ sudo su -
Password:
root# tar cf /tmp/etc-opt-cisco.tar /etc/opt/cisco-vpnclient
tar: Removing leading `/' from member names
root# ls -l /tmp/etc-opt-cisco.tar
-rw-r--r-- 1 root wheel 4167680 Oct 26 14:27 /tmp/etc-opt-cisco.tar
root# exit
logout
$ cp /tmp/etc-opt-cisco.tar $HOME
So now, in your $HOME folder, you have a .tar file with all your Cisco configs. Copy this file to a USB drive or other place so that the OSX 10.5 install doesn't overwrite it.
$ sudo su -
Password:
root# cd /etc/opt/cisco-vpnclient
root# tar xf /Users/YOURNAME/Desktop/etc-opt-cisco.tar
root# exit
$ logout
This will extract the tar file into the right place. Now, fire up the Cisco VPN client and you will see your previously-configured entries -- hooray! Don't hestitate to contact me or post a comment if you have any issues.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071026143652321