OpenSolaris was lacking virtual console for a while. This support was made available since build snv_124. However, due to various bugs, it is turned off by default. To enable virtual consoles, do the following.

$ pfexec svcadm enable vtdaemon
$ pfexec svcadm enable console-login:vt2
$ pfexec svcadm enable console-login:vt3
$ pfexec svcadm enable console-login:vt4
$ pfexec svcadm enable console-login:vt5
$ pfexec svcadm enable console-login:vt6

To enable hot keys for switching virtual consoles, do the following.

$ pfexec svccfg -s vtdaemon setprop options/hotkeys=true
$ pfexec svcadm refresh vtdaemon
$ pfexec svcadm restart vtdaemon

Console security is enabled by default. What it means is that if you leave a virtual console and move to another one, the previous virtual console will be locked and you will have to provide the password to unlock it. If you don't like that, turn the security off.

$ pfexec svccfg -s vtdaemon setprop options/secure=false
$ pfexec svcadm refresh vtdaemon
$ pfexec svcadm restart vtdaemon

If you have already logged into an X session while doing this, logout and wait for Xorg to restart. After that, you should be able to switch between the virtual consoles by pressing the hotkey Alt + Ctrl + F#, where # => 1 to 7. Console 1 is the primary console, 2-6 are virtual consoles and 7 is the Xorg.