Setting up an external drive as network storage?

I'm running windows 7 on my HTPC/Laptop and just plugged in a 4tb seagate drive to the USB 2.0 port.

My laptop had an unfortunate accident a while back when traveling. The screen literally shattered but the rest of it works perfect. I replaced the internal HD with a 128GB SSD which made all the difference in the world. It has an i7 processor, 8GB memory, a 1GB Nvidia card and works flawlessly as an internet pc/HTPC on the flat screen.

Anywho I've now plugged in this 4TB drive I picked up today and would like to make it a network accessible drive that anything can see via the wifi. If possible I'd also like to be able to connect to it from hotels to stream media saved to it kind of like a slingbox. For over a year now my laptop has sat there 24/7 running and hasn't had a single hiccup. The only time it's ever needed to be restarted was after a power outage due to storms. Highly recommended!

So with the lappy running all day what do I need to do in windows to make that drive appear as a network drive that my roommate and I can connect to and store things to as well?

As for a media server, I use Plex and it works great.

I'm certainly not network savvy, but I know I've accessed other PC's on my home network by just sharing folders with the network. I think there's even a setup wizard to use home groups. Shouldn't be hard at all.