You can make QuickBooks available in a TS environment, if you give the users some extra privileges.  By extension, that means that Quickbooks 2006 will run on ANY Windows 2000/XP+ desktop without the need for local "power user" or "administrator" privileges as well.  It does not matter what Intuit tells you - you can do it this way!  Quickbooks 2006 Professional has been confirmed to work with this configuration.

Justin + Patience + RegMon and Filemon = Solution.

Justin + Google + Solution = Terminal Server Solution found as well.

I've compiled both into here, along with links that I found via Google after I'd got it working myself.

Standalone/Terminal Server (ignore steps as necessary)

1. perform a normal installation of QuickBooks (in install mode!)

2. reboot

3. enter install mode again (change user /install), start QuickBooks and activate it by entering the registration code (this is a crucial step, and must be performed immediately following the reboot

4. go back to execute mode (change user /execute)

5. copy the %system root%\Intuit folder into each users %user profile%\Windows folder

6. create a QuickBooks Users group

7. add your users to this group

8. give the group Full Control to HKEY_LOCAL_MACHINE\Software\Intuit\QuickBooksRegistration

9. give the group Full Control to HKEY_CLASSES_ROOT\.QPG

10. give the group Full Control to HKEY_CLASSES_ROOT\obja.obja

11. give the group Full Control to HKEY_CLASSES_ROOT\QuickBooks.application

12. give the group Modify rights to the Program Files\Intuit\QuickBooks Pro folder

Group Policy / OU based mass deployment

1. Create a new Security Group.
2. Add the necessary users to it.
3. Create a new policy, and link to the appropriate OU.
4. Edit it.
5. First, set the file system permissions
   We need to do the following to these two locations:
   C:\Program Files\Intuit (it will automatically 'flip it' to %Program File%\Intuit)
   C:\Program Files\Common Files\Intuit (becomes %Program Files%\Common Files\Intuit)
   1. Drill down to Computer Configuration, then Windows Settings, then File System
   2. Click Add File
   3. Type in C:\Program Files\Intuit (it will automatically 'flip it' to %Program File%\Intuit)
   4. You'll then get a permissions screen - add the security group you just created.
   5. Grant FULL control
   6. Click OK - and configure this file or folder, then: Propagate inheritable permissions to all subfolders and files
   7. Repeat for second location
6. Now, the registry.Click on Registry, right mouse click, on "Add Key".  Drill down to "Machine" which is the equivalent of HKEY_Local_Machine.
   Set permissions on these keys: (Add as necessary, granting full access to the security group)
   MACHINE\SOFTWARE\Intuit
   Then also add
   HKEY_CLASSES_ROOT\.QPG
   HKCR\QuickBooks.ATaxLink\CLSID
   HKCR\CLSID\{8E590317-1329-11D1-B70B-00805F29CD16}
   HKCR\.QBW
   HKCR\.QBB
   HKCR\.qbr
   HKCR\.iif
   HKCR\.qbx
   HKCR\.qba
   HKCR\.des
   HKCR\CLSID\{F0AD44C0-60FB-11D1-B265-00A0243F1B5C}\Intuit\QuickBooks
   HKCR\qpgFile
   HKCR\AppID\QBW32.EXE
   HKCR\QuickBooks14.Application.1
   HKCR\QuickBooks.Application.1
   HKCR\AppID\{FAC93D44-FFC2-11d1-9DEB-0008C7A08EBA}
   HKEY_CLASSES_ROOT\obja.obja
   HKEY_CLASSES_ROOT\QuickBooks.application
   MACHINE\SOFTWARE\Classes\CLSID\{6FC4F4EA-D148-4632-B77D-294117ABF807} 
   USERS\S-1-5-21-1708537768-436374069-1957994488-1153_CLASSES 
   Run a gpupdate /force on the workstation will cause it to pull the latest OU information.
7. Also make sure that clients use short names for printers if they need to print to a redirected local printer. QuickBooks cannot handle long printer names.

Obviously, without Group Policy, just use regedit or regedt32, and set these registry permissions.  File system permissions can also be set manually on the machine.  No brainer.

Further reading:
320185 - HOW TO: Use the CHANGE USER Command to Switch to Install Mode in Windows http://support.microsoft.com/?kbid=320185

186498 - Terminal Server Application Integration Information http://support.microsoft.com/?kbid=186498

Source http://www.quickbooksgroup.com/webx/forums/canada/54

Group Policy Permissions Delegation: http://www.sbslinks.com/lua2.htm