Not free, and as far as I know there are no free IPSec clients....
MS's is a PPTP client, works, with the MS RAS/VPN solution using PPTP and that's it....
See here..
http://www.certicom.com/products/movian/movianvpn.html
I know that there is at least one other commercial, but I have not used it, nor do I remember it... I can tell you that I bought MovianVPN a long time ago, and have used it to connect to Cisco/Altiga VPN concentrators, and CheckPoint Firewalls....Even used it to connect to my LinkSys VPN router....