A breath of fresh air: Windows Mobile 6.1 for the Samsung Ace.  Finally.

http://www.samsungmobileusa.com/i325/upgrade/

I'm blogging this from my laptop, tethered to my Ace.  It's no long necessary to "unlock" the device, as they've set the security profile correctly to allow installation of apps.  To tether a newly updated Ace:

The best Windows Mobile SmartPhone in the world just got better:

• Download Sprint Developer certificates here: http://developer.sprint.com/show_thread.do?forumId=116&threadid=25821
• Copy sdkcerts_samsungAce_signed.cab to your device, install and reboot.
• Download the Windows Mobile device Security Configuration Manager (SCM): https://www.microsoft.com/downloads/details.aspx?FamilyID=7e92628c-d587-47e0-908b-09fee6ea517a&displaylang=en
• Install the Security Configuration Manager.
• Copy c:\Program Files\Microsoft\Security Configuration Manager\tool.cab to your device, install and reboot.
• Connect the Ace to your PC.  When Windows Mobile Device Center (or ActiveSync on XP) has connected to the device, load the SCM.
• A locked Ace will show as configured to set to "Two Tier Prompt".  Select "One Tier Prompt" and click Provision.  Disconnect and reboot your device.
• Note: At this point you have enabled unsigned software installation on the Ace, as well as enabled Registry editing on the device.
• On the Ace, download the PHM Registry Editor for SmartPhones: http://www.phm.lu/downloads/download.aspx?{940B734A-C437-41C7-ADED-2A4418802FD3}
  • Agree to the license, then select the "Smartphone 2002/2003 (ARM/PXA)" download.
• Install and run the Registry editor.
• Locate HKEY_LOCAL_MACHINE\Comm\InternetSharing and remove the value "InternetSharingEx.dll" from the key "Extension".
• Reboot the phone.
• Attach the Ace to your laptop.
• On the Ace, go to Start and "Internet Sharing", and hit the Connect softkey.  Your laptop should see a new NDIS device, and automatically connect to the Internet.