My DSL Internet modem is connected to a switch and all pc's in our home are wired thru
this. My problem is that, if one user downloads a lot the other pc's gets timed out when connecting thru the internet.
Is there a tool/software that can equally divide my DSL speed to all users so that not only one user is
getting all the bandwidth? I am looking for a free option actually.
Not really, your best option is probably to enable QoS on your router and assign a low priority to the download protocols in use, be it FTP, torrents, or other. That way, they'll go full speed when times are slow, and back off when your network is being used.