Okay, I have a wireless network set up in my house that my and my dads computers are connected to. We have a printer although its connected to my dads laptop via usb.

If I wanted to connect it to the network so that I could use it from my desktop, do I just have to connect the printer to the router with an ethernet cable?

Or do I have to mess around with any settings on the router? As I don't have the login details to access the control panel for the router!

Depending on the printer you would just share it on the machine it is plugged into.

HOWEVER!
You'll probably find it won't print across a network. If the printer has been marketed as a SOHO or "Home user" machine, network capabilities are killed in the driver on the host machine.
What you will need to do is buy a USB print server and plug that into the router, give it a fixed IP, plug in the printer then configure the machines to use a TCP/IP port for printing. The server then handles queuing and job collisions etc.

unless the printer really does have a network socket??? If so connect it to the router/switch and set an IP on it. Other PCs connect to the printer via it's IP

if connected to a PC, then you should be able to SHARE it by going into it's properties (From the Printers control panel). Give it a name, then connect from other PCs using the IP of the PC it's connected to \ printer name

Thanks, Ill see what I can do!