The IETF is the primary protocol and standard building group
on the net. The IPSEC, ISAKMP/Oakley and DNSSEC standards are
being developed via the IETF Working groups and the people who
volunteer their time, resources and effort to the task.
IETF
IPSEC & ISAKMP/Oakley Workgroup
IETF
DNSEXT Workgroup (where DNSSEC work is done)
The KAME project has written IPSEC for FreeBSD, NetBSD and OpenBDS, their home page is over at: http://www.kame.net/
There is an international trade association for manufacturers in the VPN market at: http://www.vpnc.org
Just to plug some great folks who have contributed much to the community, SSH inc. not only does the fantastic SHH2 suite of software but also does a broad line of commercial IPsec products, just in case your still running something becides Linux... :r)