I used to use TheGreenBow for VPN back to my home system via a Linksys
router, but it doesn't run under Vista. Microsoft has a list of
Vista-compatible VPN clients. On Thursday, they added the Fortinet VPN
client. I just tried it and it works great -- lightning fast and rock
stable. As far as I can tell, it's the first Vista-compatible IPSec client
(I've been using TheGreenBow in XP Pro running in a Microsoft Virtual PC
window -- far more of a pain than it should be. I can't figure out pricing
from the website, but I've emailed to ask. Anyway, if you're looking for a
good IPSec VPN client that will run under Vista, check out Fortinet.

(And, no, I have nothing to do with Fortinet. I just needed a VPN client.)