You need to shutdown the VM

Then log on to the console of the Host server

Change to the directory that contains the VMDK (you can just pass the full path to the command line but I find this less confusing)

Type the command:  vmkfstools -X <size> G <VMDK file name> (note that G stands for gigabytes so to expand a disk to 32 GB it would simply be vmkfstools -X 32G some.vmdk).

Type ls -lh and you should see the VMDK is now that size. 

At this point you must use the OS tools to in order to see the additional space.  I don't kow how this is done in Novel but in Windows I use the 'diskpart' tool.

Good luck

p.s. of course you make a backup first

the before mentioned vmfsktools work perfectly, if your not a pro in linux command line use, you could possibly also use the vmware converter to expand your vm.

anyhow, the command line description is way faster when u know what you are doing ^^

If you are running ESX 3.5/VC 2.5, VC now has the option to extend the VMDK file through the GUI as well.  I've used it a number of times so far and haven't had any problems.

--Dave