If you have a CPU with hardware virtualization support you can run JNode in kvm wich is much faster than vmware-[player|server] (at least for me). You need a CPU that either supports Intel's IVT (aka Vanderpool) or AMD's AMD-V (aka Pacifica).
With
egrep '^flags.*(vmx|svm)' /proc/cpuinfo"
you can easily check if your CPU supports VT or not. If you receive output your CPU is supported, else it is not. If your CPU is supported also check that VT is enabled in your system bios.
Load the kvm modules matching your CPU, either "modprobe kvm_intel" or "modprobe kvm_amd", install kvm user tools and setup permissions so users may run kvm (Have a look at a HOWTO for your distro for details: Ubuntu, Gentoo).
Once you have setup everything you can start kvm from the commandline (I think there are GUI frontends too, but I'm using the command line). You should be carefull though, acpi in JNode seems to kill kvm, so allways disable acpi. I also had to deactivate the kvm-irqchip as it trashed JNode. The command that works for me is:
kvm -m 768 -cdrom jnode-x86-lite.iso -no-acpi -no-kvm-irqchip -serial stdout -net none -std-vga
The "-serial" switch is optional but I need it for kdb (kernel debugger). If you want to use the Vesa mode of JNode you should also use "-std-vga", overwise you will not have a vesa mode. Set the memory whatever you like (768MB is my default).