Here is a three part screencast that provides an example of implementing a high speed 3Mb/s UART with the Papilio One board and the FT2232 USB chip.
The project uses the free Xilinx VHDL UART example because it is optimized for Xilinx hardware, it provides the smallest and fastest UART possible. The source code requires an end user license agreement which prevents us from providing the source code. Part one of the video tutorial walks you through adding the source code to the project after it has been downloaded from Xilinx.
Please click the link to view the rest of the videos.
Followup – Changing the ISE project for use with the Papilio One 500K board