The Saleae Logic's main component is a cypress CY7C68013A
http://www.cypress.com/?rID=14181



CY7C68013A, CY7C68014A, CY7C68015A, CY7C68016A

Last Updated: 07/15/2009

EZ-USB FX2LP™ USB Microcontroller High Speed USB Peripheral Controller

Features (CY7C68013A/14A/15A/16A)

    * USB 2.0 USB IF High Speed Certified (TID # 40460272)
    * Single Chip Integrated USB 2.0 Transceiver, Smart SIE, and Enhanced 8051 Microprocessor
    * Fit, Form, and Function Compatible with the FX2
          o Pin compatible
          o Object code compatible
          o Functionally Compatible (FX2LP is a superset)
    * Ultra Low Power: ICC No More than 85 mA in any Mode
          o Ideal for bus and battery powered applications 
    * For more, see pdf

Functional Overview

USB Signaling Speed

FX2LP operates at two of the three rates defined in the USB Specification Revision 2.0, dated April 27, 2000:

    * Full speed, with a signaling bit rate of 12 Mbps
    * High speed, with a signaling bit rate of 480 Mbps. 

FX2LP does not support the low speed signaling mode of 1.5 Mbps.      More...



This hardware can be programmed using open source tools that can be downloaded from here
http://volodya-project.sourceforge.net/fx2_programmer.php

the example here http://volodya-project.cvs.sourceforge.net/viewvc/volodya-project/8051/ex2/
works after modifying the build shell script to use the logic analyzer's bus

The on-board firmware allows to set output values see the LogicConsole.

Some thing that might be nice to try:
Get this code running:
http://www.ixo.de/info/usb_jtag/

The 8 outputs of the logic anzlyzer are attached tot portB

Some other code that works is the advanced examples located here (creating a ftdi serial emulator)
http://www.triplespark.net/elec/periph/USB-FX2/software/advanced_examples.html#convert_serial
