This leads me back to an unanswered question. Will
fusion incorporate an easier process to increase the
physical size of the virtual hard drive in future
releases (eg, increase the maximum size of my virtual
hard drive from 6gb to 12gb), as opposed to the one
outlined by Pat Lee? If so, when?
Well....let me say two things to that...in general VMware does not provide any information about future functionality or their availability.
Having said this, I know that people have requested an easier way to deal with certain things such as the configuration as well as virtual disk management...so I guess there is a good chance to see something in a future release...
Ciao, Andreas
PS: I do not work for VMware though, so the above is my own opinion... 
It seems that Parallels and Fusion both have this
"expanding hard drive" feature, just that parallels
markets it a little more.
Aha, I think I figured out the source of the confusion here. In Parallels's Hard Disk Options screen, there's a checkbox for "Expanding." But, in Fusion, the equivalent feature is always used by default, and there isn't even a way to turn it off in the user interface. (We do provide a separate tool for converting an expanding virtual disk to a fixed-size virtual disk, called "vmware-vdiskmanager", about which I will say more below.)
I assigned a maximum of 6gb physical space to my
virtual hard drive and have already used 5.8gb. I
understood "expanding hard drive" to mean that this
6gb would grow (eg, always leaving 1gb of physical
free space for the virtual hard drive to expand
into).
Hmm, I am afraid you may have misunderstood the nature of expanding disks. Virtual disks (Parallels or VMware) don't auto-grow past their maximum sizes. I'd consider it a bug if they did!
My copy of Parallels 3.0 (build 4560) comes with a separate program called "Parallels Image Tool" that can enlarge a virtual disk's maximum capacity. But you have to run it explicitly, and you must do so when the VM is powered off. That's not a criticism of Parallels. In fact, VMware's vmware-vdiskmanager is also capable of enlarging a virtual disk's maximum capacity, and it too must be run when the VM is powered off.
Frankly, Parallels Image Tool and vmware-vdiskmanager both do the easy part of enlarging a virtual disk. The hard part is the file system inside the virtual disk: it has to grow somehow to take up the new space. And, if it was a boot disk, it needs to have its boot sector corrected to the new disk geometry, so that it'll still boot. This problem is why the makers of Partition Magic have made a lot of money. And, in fact, Partition Magic works just as well inside virtual disks as inside physical disks.
In Pat Lee's "how to grow a virtual disk" writeup, most of the heavy lifting is in fact devoted to this second problem. He has the reader download and use gparted[/i], a free alternative to Partition Magic.
In fact, if you check out the "Parallels Image Tool User Guide," you'll notice that it does not even attempt to explain how to enlarge your existing filesystem. Rather, it takes the simpler path of having you create a new partition in the newly created space and put a new, separate filesystem inside. As far as I know, you could use Pat's instructions just as well with your Parallels VM, substituting Parallels Image Tool for some of the early steps. Maybe Parallels should send Pat a check! 
Could all this be made easier? Well, to a certain limited extent. Our tool could use a graphical user interface. (Our colleague Eric Tung wrote a nice one that's a free download from this forum; it's not an official part of Fusion, and it's not supported, but it is mighty slick.) And Parallels Image Tool (build 4560) doesn't work on every kind of Parallels virtual disk, although vmware-vdiskmanager does work on every kind of Fusion virtual disk. So I'd say we're sort of even.
As Andreas says, VMware people never talk about unannounced features. In fact, I'm not even a member of the Fusion team, just a random interested VMware employee.