The Orca MSI Editor is a table-editing tool that can be used to edit .msi files.
Orca MSI Editor allows the properties of any MSI file to be edited. It is possible with Orca to, for example, change the title and text within the installer and look at how and where the files are delivered. Once installed you can right-click any MSI and select Open with Orca.
For more information about what it does and where to find it, take a look at Orca.exe page which is part of Windows Installer Development Tools.