Hello guys
Please i need a site link to where i can download a software for circuit design and simulation.

 

http://www.linear.com/designtools/software/#LTspice

 

Hello,

Have a look here:
http://educypedia.karadimov.info/electronics/easoftsim.htm

Bertus

 

http://www.linear.com/solutions/ltspice

 

circuits cloud is online simulator and free
you can try it
http://circuits-cloud.com/

 

As others have suggested LTspice is a good one.
Several on these forums, including myself, use it and it's probably one of the best free analog simulators available.
There's also a Yahoo LTspice users group which can help you get up to speed.