I have installed OpenSolaris (specifically, Solaris Express Community Edition build 91) on my new home server which will consolidate three existing (rather old, noisy, and underpowered) machines.
I am installing Postfix as my mail server software. I created an smf(5) service manifest for postfix so that I can have smf start it. Contrary to the (IMHO misguided) common practice, I install manifests in /lib/svc/manifest/. So I installed the above file as /lib/svc/manifest/network/postfix.xml and used svccfg import to create the svc:/network/smtp:postfix service instance.
[Update: Normally I would have offered this file to the smf community and/or the Postfix author/maintainer, but before I posted this others had already beat me to it.]