As you already know, the HST is to be implemented July 1 2010.
I will try to satisfy all request for explanations in this communiqué, please see below.
The provinces of Ontario and British Columbia have enacted legislation to implement the harmonized sales tax (HST), which will replace existing provincial sales taxes and the federal goods and services tax in those provinces beginning July 1, 2010 and will be administered by the Canada Revenue Agency. The transitional rules for the proposed HST would apply to certain transactions that straddle the July 1, 2010 implementation date.
For users of the ImEX shop management system and the QuickBooks accounting system, the modifications regarding the HST implementation will require 3 steps:
Step 1 includes updating the QuickBooks accounting software to version 2010 release R4P. You can verify your version of QuickBooks and the release number by following these steps:

1. Start QuickBooks; wait for the program to load.
2. Hold down the “Ctrl” key and press “1” on your keyboard, wait for a window to open.
3. Your screen should like the one below.

If you do not have QuickBooks 2010, please call Intuit, the developer of QuickBooks accounting software at (888) 333-8580 to request the latest version of the software. If you are an existing QuickBooks user and a subscriber to the payroll package, there should be no charge for the upgrade from Intuit.
Once your software has been updated to the correct version, you must update your company accounting file to version 2010 R4P. Usually, this is a straightforward process. For clients needing assistance updating the company file, we can complete the update for you. The charge for this service can be estimated at $75.00 to $125.00 depending on the file size. To request assistance, please send an email to hsthelp@thinkimex.com with “QB 2010 Update” as subject, stating your shop’s name, contact person’s name and the login and password to access the data file. Requests without login/password cannot be processed, as we will not be able to access your file. To be fair to all clients, all requests will be completed on a “first come-first served” basis.  Please note that updating of accounting files version 2007 and older will require additional modifications of the chart of accounts and item list. The price quoted above does not include those modifications.
Step 2, to be completed at the end of June 2010, includes modifying labor and tax rates setup in the ImEX system. We will most likely make this update available as a download from our website as a self installation file. There will be NO charge for this update.
Step 3 includes modifying the QuickBooks data file right prior to the implementation of the HST. Among others, the items list, vendor’s list, customer list and tax codes list may have to be modified to accurately work with the new HST tax. Information about the changes required can be found at:
www.quickbooks.ca
http://www.cra-arc.gc.ca/tx/pstr/trnstnl/menu-eng.html
You can also contact your accountant or Canada Revenue Agency for additional information.
Optionally, we can assist you with those tasks. The cost for this service can be estimated at between $50.00 - $90.00 depending on the file size and number of items needing modifications. To request assistance, please send an email to hsthelp@thinkimex.com with “ITEMS HST MODIFICATIONS” as subject, stating your shop’s name, contact person’s name and the login and password to access the data file. Requests without login/password cannot be processed, as we will not be able to access your file. To be fair to all clients, all requests will be completed on a “first come-first served” basis.  
Please direct additional questions regarding this topic to hsthelp@thinkimex.com and I will answer them promptly.