|Of course, if you want to use this class, you're going to need some QBXML files. |
If you're just starting out, I suggest signing up with the Intuit Developer's Network (IDN) at ( http://developer.intuit.com ).
The QBSDK is provided free of charge by them and registration just takes a minute. A basic IDN membership is free also.
There is also quite a bit of QBSDK related documentation at my website http://qbopen.com
I developed this documentation as part of my consulting practice and often provide "tier-2" support to IDN developers, which leads to consulting projects of one kind or another.
Drop me a line if you find the QBRDS Client class or info at http://qbopen.com useful, or if you think you need help with your QuickBooks integration project.