tap interface - 10.6.x

I need to create a few tap interfaces, before I used an open source product called TunTap ( http://tuntaposx.sourceforge.net/). This doesn't appear to work on 10.6, I've removed Cisco VPN and VMware as part of the trouble shooting process without luck.

Is there a built in method to create tap interfaces on OS X 10.6 now? Are you aware of any product which will?

thanks,
greg