What exactly... is it? I have a general idea of what it is, but I don't know about its features or anything. I'm thinking of changing my hosting, and I might get it soon.

So, can anyone explain it to me?

It's a place that you go to on your browser that controls your hosting. You can add/subtract emails, subdomains, domains, play with MySQL, features (i.e. Wordpress, phpBB, etc).

It's easy to get a hang of.

it lets you manage files, check email, and theres fantastico which lets you instll in one click, also you can set up ftp accounts and set up quotas :]

cpanel is the best hosting control panel i have ever used. Its very simple to use and easy to operate, You can add domains, emails , FTP accounts etc... can manage all domains hosted under your cpanel account. You can also upload all webfiles using its File Manager tool. You can get traffic details for your domains. You can also install blogs, shopping carts, guest book etc... using Fantastico :)

cpanel is very popular and is widely used control panel.

what everyone said before
but here's an actual example were you can click on the icons
cPanel