Podcasting – it might sound like a fishing expedition on Mars, but in fact it's the latest and greatest tool in the online activist's repertoire. A podcast is a home-brewed piece of audio downloaded directly to an iPod – hence the name – or MP3 player.

What a podcast contains is up to you: it's a DIY radio programme in which you're editor, producer and host. To 'go live', you simply upload what you've recorded to the internet. Then some nifty software takes care of things, scanning lists of podcasts and downloading users’ selections from there.

Right now, podcasting has a pretty niche audience – a successful 'cast' isn't measured in millions of listeners, but hundreds. But that's just an opportunity for you to get in on the ground floor, isn't it? Remember, there's nothing to censor you now but the 'stop' button on your listeners' iPods.