change target for a simulated target

[msarasa@fh-konstanz.de]

I have to make Gdb work with a simulated target instead of with the real 
target that works now. What should I do? , tell me please the steps I may 
follow in order to change the real target that we use now via serial link for 
a simulated target . I have the simulator , but i've no idea how to begin. 
Does anybody have done that yet? could i see some code? or , how to begin? 
It's very important, please, i need that for my Thesis. 
Vielen Dank, Thank you very much