Regardless of which NI GPIB controller product you use - PCI, PCMCIA, USB, or ENET - you can use either NI-488 or NI-VISA. Both APIs are independent of the underlying bus connection hardware type.
You can also use each API with C (eg, using LabWindows/CVI or MSVC) or C++ or C# (eg, using Measurement Studio and MSVC) or LabVIEW. Each API is tuned slightly for the particular development environment, but the concepts are the same.
Dan Mondrik
National Instruments