See www.FTDIchip.com They do a USB interfaces that 'looks' to software like RS232, but can run a lot faster. In fact, the interface chip can be programmed in parallel mode, which makes the baud rate almost meaningless.
At the PC end, you can either use the FTDI DLL for full interface functionality, including additional FIFO modes, or just use your programming language's own serial com port interfacing, to teh virtual USB com port. <http://www.FTDIchip.com> -- Andy G4JNT www.scrbg.org/g4jnt
