IP security document roadmap [SECARC2401] is a great source of information for understanding the details of how an architecture based on IPsec should be designed. This RFC is being modified at the time of this writing [SECARCDR] and will be soon be replaced by another RFC.
For more information on IPsec, IKE standards, and progress on IKEv2, the reader is referred to the IETF IPsec working group official website [IPSECWEB].
Readers interested in open source implementations of IPsec may refer to the FreeS/WAN project web site [FREESWAN].
The IETF web page for TLS working group can be found at [TLSWEB], while information on open source implementations of SSL can be found at [OPENSSL].