You can definitely do this.
The main thing you need to configure to activate these features is MC's Media Network feature. The options for this are found under
Tools > Options > Media Network. The main things you need to do are:
1. Turn it on.
2. Add a Username and Password (this is required to allow remote devices and copies of MC to make changes to MC's database, otherwise it runs Read Only).
3. Configure the Media Network Views that will be used by your devices. These are
separate from the Standard and Theater views you have in MC, though they have essentially the same capabilities. These are configured via
Tools > Options > Media Network > Advanced > Customize views for Gizmo and WebGizmo.
Also, you may want to:
1. Set MC to run in the background in Media Server mode (which will allow this stuff to work even when MC itself isn't "running"). Go to
Tools > Options > Startup > Windows Startup, and
pick one of the choices that includes Media Server.
2. Enable port forwarding for the port used by MC's Media Network on your home Firewall our Router, so that any traffic it receives from the Internet on that port gets forwarded to the computer that is running MC. Because there are such a wide variety of possible options here (depending on the gear you have), this is hard to assist with specifically, but
this Wiki article should help get you started (also check out
this thread). You may need to
do the same on the built-in Windows software firewall.
Port Forwarding will allow you to connect to your copy of MC that is running "inside" your home network, from computers and devices running "outside" your home network. Without it, you will most likely only be able to connect to MC while you are at home and connected to the same router/network on which your PC resides. This isn't a huge deal if you only intend to use this to remote control MC, but this system also allows you to stream content from MC to your mobile devices. That's a pretty big deal and is a very nice feature, so it is worth setting up.
Then...
Once that is all done, you should be able to connect to MC's web server from your mobile device or other computers. There is some coverage of this in
this Wiki article, but basically, you want to open:
http://webplay.jriver.com/libraryserver/lookup?id=[Access Key]
(replacing the Access Key in that URL with your actual Access Key defined in Options > Media Network.)
From inside your network, if you know the IP address of the machine running MC, you can also connect directly via:
http://[SERVER_IP_HERE]:[PORT NUMBER HERE]
That's enough. MC's Media Network includes a "Web Remote" feature called WebGizmo that provides a basic interface for most of these features. You can, if you choose, just use that (make a bookmark to it on your home screen) and you get a lot of the basic functionality. However, for a much-improved "native app" experience, I highly recommend
JRemote. This is a third-party app in the iOS App Store that is a full-featured MC Web Services client. It can stream audio to the device, and fully remote control copies of MC running on any platform.
It is very nice. I use it pretty much every single day.