Here are two Sysgen tutorials that show how to interact Xilinx and Matlab on DSP projects.  They are both 20MB each and you will need a sound card to hear the audio.  They both come from the following web site courtesy of Xilinx Corporation. (Xilinx Home: Products: Design Tools: Xilinx System Generator).

Xilinx System Generator Demo (20MB)

Functional Simulation Synthesis and Implementation Demo (21MB)