I have a 2TB external drive that I'd like to connect to my wireless router so that I don't have to move it around all the time depending on where I'm using my laptop.
I plugged it in to the router, and the lights come on so it "knows" it's connected, but it's not showing up anywhere on my computer.
What do I have to do to get it to work?
You may have to format the drive using your router's settings so it can allow the drive to work, log to your router's configuration page by typing the IP address of your router on an internet browser. It should have a section for setting the drive over the network, if the drive is not there then the drive is not compatible with the router for that functionality.
I also have two other drives that I'm not currently using - both WD - one is firewire, but has a USB port on it, the other is USB only. Can I hook all three into a USB hub and then connect the hub to my router and access all three drives?
Yes you can, if your router supports it. Check your router's user manual or check the manufacturer to confirm if it can be done with the one you have.