Upgrading your DMP1's hard drive is fairly simple.
Overview: The Omnifi DMP1 comes with a 20GB drive.  While sufficient
for some, I wanted more.  This guide steps you through the process of
replacing your factory drive.  As always, modifying your Omnifi in any
way will void your warranty.

To get started, you need a T6 Torx Driver (try your local Sears store)
and replacement 2.5" laptop drive. My Omnifi's drive is a Toshiba MK2018GAS.
It's my understanding that not all model hard drives will work with
the DMP1.  If you have done this mod, please e-mail what drives have
or have not worked for you so I can update the list.

Because the system uses FAT32, I'm guessing there will not be any problem
using drives up to 137GB, but beyond that still needs to be tested.  It
looks like to drive is actually talking to the Omnifi via USB, so I doubt
we'll have the IDE channel issues of using 137GB+.  If you'd like to donate
a drive, I'll be happy to test it.  :)

Unfortunately, Windows XP/2000 doesn't like to create FAT32 partitions
bigger than 32GB. So you'll need to use a utility like Partition Magic or 
Partiton Manager to create your partition.  I used the free Demo version of 
Partion Manager 5.5 to upgrade to a 60GB hard drive.  Download it here.  

Remove the 10 T6 torx screws from bottom of drive. Congrats! You have now officially voided your warranty. :)
Separate the two halves. Be careful not to lose any of the screws.
Remove the 2 T6 screws holding down the PCB
GENTLY peel back the shielding & separate drive from the PCB. Be careful with the wire that operates the front eject button / LEDs. I taped my to the board.
Now attach your new hard drive to the controller PCB & reassemble.
Plug the newly assembled drive cartridge into your PC's USB port. Don't forgot the power cord too! We'll need to make sure it's formatted correctly. The DMP1 uses a FAT32 file system.
Start up the free Demo of Partition Manager 5.5
Find your new Hard Drive. This should be listed as Drive 1 or greater.
Right click on the drive and choose "Create".
Select the partion size (slide the bar all the way to the right).
You should now see your new, unformatted partition.
Right click on the new partion and choose "Format".
Set your volume name to "OMNIFI", choose FAT32, and uncheck the "Surface Test" box.
Click "Yes"... The message should read: FAT32 is only accessible under Windows 95 OSR2/98/ME/2000/XP, Linux, and Omnifi
There it is! Your new Omnifi drive.
Now "safely" remove your DMP1 hard drive from the PC.
Here's the cool part... The Omnifi DMP1 will automatically "initialize" any blank FAT32 hard drive that gets plugged into it. So, plug your hard drive cartridge into the DMP1 and power it up. You should a message saying that the drive is being prepared. The DMP1 creates "\USR\root.xml" during this process.
If your Omnifi gets stuck in a continous loop, do not fear... Simply plug your drive back into the PC. Find the file in the USR directory call "newroot.xml" and rename it to "root.xml"
Once you see "[Media Unavailable]" on your DMP1 controller, your hard drive is ready to be sync'd. Plug the drive cartridge back into your PC and use SimpleCenter to synch.