For those who come across this forum topic later with the same
question...
You can see examples of how to do Win32Ole / COM in the demo QuickBooks
rubygem, available at http://rubygems.org/gems/quickbooks.
The full version is available for sale at http://behindlogic.com, but if
all you want is the COM communication, you can get that out of the demo
gem.
Also available at http://behindlogic.com is an HTTP Connector that makes
it possible to use the gem (or other quickbooks-integration project in
any language) from a different computer.