Design Methodology

One little question.

Can anyone support me with link to web-sources where design methodology of system on chip is discussed. I want to find info about using corss-tools in designing. For example usage of Matlab Simulink and ModelSim for hardware co simlation with mathematical models.

Also cause I need to migrate to Xilinx can anyone point me to the same-style discussion forum but dedicated to Xilinx.

Thanks beforehand.