At present I have a wireless network in my house (3 pc's). They all have 54mbps pci cards. Im thinking of chaging it around so its all wired using ethernet cables.
Will this make the internet faster? Im assuming it will
It won't because the wired connection is faster than the wireless. The only way that it will speed up is if there's interference in the wireless signal, from other sources or just simply walls in between the router and computers.
So yes, you will probably see some speed increase if you get any interference at all (do you get full signals?), but you may not notice that much.