Pretty simple to share a printer. Hook up the printer to one of the computers, install the drivers, right click on the printer after install and go to 'Sharing & Security'. Finish the wizard and it will be shared over the network.
You will want to run the network setup wizard on each computer and make sure that you have typed in the same name for 'Workgroup' on each computer.
After that, "Add Printer" on each of the other computers, select 'A printer attached to another computer over the network', then browse your network for the shared Brother printer, select it and hit next. Finish that wizard and you are good to go.
If you would like it to be a true 'network' printer, you will want to buy a print server that is compatible with your printer and model.