Since Windows Vista has not officially released anything is subject to change, but I will do my best to answer your questions.
Vista 64bit will require that all kernel mode components are digitally signed. These components may be signed by Microsoft through the WHQL program, or they can be signed by the publisher (In our case National Instruments) using a code signing certificate. Vista 64 bit will be adding this requirement simply so customers can verify that the software they are installing has not been tampered with and, assuming they trust the publisher, are not installing malware.
Your question was directed at the DDK, however you did not mention which DDK. Most of our DDKs are distributed as source code for example the Measurement Hardware DDK. This source code allows you to create a kernel mode driver for your OS. In this case you (as opposed to National Instruments) would be responsible for either submitting the driver to WHQL for Microsoft to sign, or purchase a code signing certificate from a vendor like Verisign, and sign it your self since you are the publisher.
Another example of a DDK is the VISA DDK which you can use to write user mode drivers for your hardware. VISA itself does use kernel components, and they will be signed by National Instruments, however since your resulting driver is all in user mode it does not NEED to be signed. If it is not signed you will receive a message indicating that the driver came from "Unknown Publisher". You can always make this message go away by digitally signing the driver your self with a code signing certificate.
You also asked whether GPIB/DAQ will be releasing "64bit Signed Drivers". As previously mentioned all kernel mode drivers for Vista 64bit will require a digital signature so all kernel drivers that we release for Vista 64 bit will meet this requirement. The majority of our drivers will likely be signed by National Instruments to clearly indicate that we are the publisher, but on a case by case basis some drivers will be submitted to WHQL and signed by Microsoft.
Hopefully that answers your question. But if not feel free to ask.
Shawn B.
National Instruments
