To control multiple PCs from single computer?

[mukta22]

Hi..
i am using 2 computers @ home and third is about to buy.
Now what i want is a software that can allow me to have common input device say a mouse & keyboard which can control other two PCs. Is it possible is there any software? Any client server tool? I will make my new laptop the server or anyone of those 2 PCs? It will be better if it's free.
Thanks,
mukta22

[Gian]

What operating system you have on these computers?
Do you have Windows or linux?

[mukta22]

I have both os installed on different PCs.
Is there any utility with the operating system itself?

[SuperXCM]

Hey you need to set up an server client environment with your 3 machines.
Make sure what will be your server? then you can control the other two client PC automatically. I think this will do what you want to do. Why you need a software?

[SAeLac]

I think this is what you want for your purpose.
Multiplicity

[Bhairav]

These are some tools & softwares.