I've come to the conclusion that DLNA is the secret sauce of the digital home. Of course DLNA isn't a secret, I've just never paid that much attention to it before.

DLNA stands for Digital Living Network Alliance. It's basically a standard protocol for streaming audio, video and photos between devices on your network, and it's built into a growing number of products including the PlayStation 3 and the latest Sony Bravia televisions.

DLNA requires two components - a DLNA server and a DLNA client. The DLNA server is usually a computer, running DLNA media server software such as Windows Media Player 11, TVersity or PlayOn. The DLNA server can also be a Network Attached Storage device. Your DLNA server holds all your content, plus some server software lets you connect to the internet to pull down stuff like internet radio and television clips from sites like Hulu. Of course if you want to access US-only sites such as Hulu, you'll need to be running Virtual Private Network (VPN) software to make it appear as if your DLNA server resides in the land of the free and the home of the brave.

Once you've set up your DLNA server it advertises itself on your home network, waiting for a DLNA client or two to come along and connect. The great thing is that there are a lot of devices out there with built-in DLNA, giving them access to a whole range of extra content that they'd never usually be able to play. For example you can use a PlayStation 3 or an Xbox 360, or even a modified Xbox or Apple TV. It's a shame there doesn't seem to be a DLNA client for the PlayStation 2, as they're dirt cheap right now and there's an optional Ethernet adaptor.

There are plenty of DLNA-compliant, dedicated media players and the protocol seems to be creeping into mainstream DVD and Blu-ray players. You can also get a DLNA client to run on your computer - such as XBox Media Centre, a media player interface which has been ported toWindows, Mac and Linux as well as modified Xboxes and Apple TVs. DLNA is even built into some Ethernet-enabled televisions from the likes of Sony and Samsung, although the first generation of DLNA-compliant Sony Bravias would play audio but not video.

Some DLNA servers will even transcode video files on the fly, changing them to a format that your DLNA client can play - something that is important if you're using a device with limited format support such as the PlayStation 3. On the fly transcoding obviously requires a lot of grunt on the part of your DLNA server, so you might be better off looking for a more flexible DLNA client which can natively handle the widest range of formats. XBMC is a good place to start.

The reason why I started looking at DLNA is because I finally caved in and bought an Apple TV recently, but only so I could hack the bejesus out of it for a magazine feature. It's simple to hack the Apple TV by loading on software using a USB stick, after which you can use software such as XBMC and Boxee to stream all kinds of great content from your network or the internet. There's even an Apple TV VPN client, called BoxeeVPN, but I couldn't get it to work. Apple released the 2.4 software update for the Apple TV just before I bought one, which played havoc with a few of the software hacks, and this might be the cause of my problem.

Without a VPN I can't watch Hulu. I toyed with ideas such as using a VPN-compatible router, or running a VPN on a computer and then connecting the Apple TV using Internet Connection Sharing, but neither of these seemed like elegant solutions. Then I remembered that XBMC is a DLNA client, so the easiest solution is to run a DLNA server on my media centre as well as a VPN such as Witopia, and then use XBMC on the Apple TV to pull content off the media centre. DLNA server software such as PlayOn and TVersity handle local content and also offer plugins for online services such as Hulu. Hey presto, Hulu on your TV no matter where you live. Of course things are never that simple, but at least the concept is sound.

The reason why I've never paid much attention to DLNA in the past is that I've got a Vista Media Centre PC in my lounge room, which does everything (when it works), so I don't need to stream video between devices. I stream audio around the house using iTunes, Airfoil and a few Apple Express wireless points. I recently set up a television in the rumpus room downstairs, to keep the peace when the kids want to watch Play School but I need to use the TV for tinkering with toys. I've been wondering about the best way to get all my content downstairs and now I think I have the answer - XBMC running on an old PC with a DVD drive to cover all my bases. It certainly seems like the most elegant solution for my digital home.