Sorry, I've got ahead of myself - it's been one of those days.

It is a VMware image I was talking about but it's only version 4.0 at the moment. The reason there's no demo available is that it's still in beta, there isn't even a beta of the NE version available yet only the OSS version.
If you want to install VMware you could always install the OSS 4.5 RC1 version to get a feel for the features, when the NE edition becomes available it would just be an upgrade to get it running. I'm sure you've read this already but just in case, the NE version must be installed on RHEL4, SLES10 or MAC OS X. If you don't want to get a subscription to RHEL or SLES yet you could install CentOS as it is binary compatible (and free) with RHEL.