If you are using Great Plains 8.0 you can download the Payroll Tax Update (Round 4) file by clicking here. Keep in mind that this script was developed for version 10, but runs just fine on version 8.
I strongly encourage you to execute the script in a test environment to make sure the results are what you are aligned with your expectations. Once you've verified this, you can proceed to execute against your production environment.
NOTE: They were additional changes included in a separate installation file to update Missouri's tax code. This script does not include those changes. I am in the process of working on the new installation file and will post back with the updated tax rates for Missouri. In addition, and according to Microsoft, The msp file for I-9 and Cobra changes will be available on March 25.
2009 Payroll Tax Update for Microsoft Dynamics GP 8.0
Until next post!
Mariano Gomez, MIS
Maximum Global Business, LLC