Freenet's very structure works like Bittorrent, so there is no need to support it explicitly. If you upload a file, you can advertise it openly, and the more people downloading it, the faster it goes and the more widely it will be spread on the network.
There is an experimental IRC over Freenet. The main problem is the latency that gives you the security doesn't work so well with IRC.
As another poster said, the main different between Freenet and I2P is that Freenet contains its own data storage. So you can connect, upload something, and disconnect (not that this is recommended for general users, but it's an option). With I2P, you have to have a webserver (or whatever) online for the resource to be available. That is a bit of a privacy risk if they knock out your server and can see instantly the "eepsite" go offline.
Freenet really is working quite well these days - people share movies, music, TV shows on it all the time, and there are a lot of interesting freesites.