I'm planing to start using USB PIC devices such 18F2550 in my projects. Could any body please recommend me a USB wrapper dll or code that help to communicate with USB PIC from visual basic.
Depends on what you want to use it for, and how you want to use it.
You can have the chip work as USB -> 232 Converter style circuit, which will basically allow you to use serial code in the controller, very very similar to the UART code.
Or, you can use HID, which is a bit more complex, you can get plenty of free code to interface a USB system, it just depends on what you need it to do.
You dont really need a wrapper, just some API calls.
I never understood why they call that project the UBW project, the chip was actually MADE to interface with USB, so it's not actually 'bitwacking'
The only USB bitwacker I've ever seen was an AVR one that used GPIO lines for a low speed interface.
You've obviously not read the site?, it's because it's designed to allow you bitwise control of a port on modern computers which no longer have a parallel port.
Nope, not a PIC guy (yet) I get it now though. With the AVR USB bit whackers the terminology was very different, It was bit manipulation of the I/O port on the AVR to create a USB slave device that emulated a serial port, they have one that does an HID compliant device as well now I believe.