Photo credit: Maxxyustas

1. Alliance: Free open-source P2P application lets you share entire folders with your friends
2. Ekiga: Free VoIP and video conferencing application for Windows and Linux
3. Coffee Cup Live Chat: Downloadable software for chatting with your website's visitors
4. TwitterCube: Upload and share images and documents up to 10MB via Twitter

1. Alliance
   
   Alliance is a free, open-source peer-to-peer application, that lets you your own file sharing network. You can add all of your friends to your network, share files, and also chat with them. The traffic between clients is encrypted at a low level, but you can apply an experimental SSL layer if you'd like a bit more protection. Alliance is a free download for Windows, Mac OS X, and Linux systems.
   http://www.alliancep2p.com/





2. Ekiga
   
   Ekiga is a free and open source VoIP and video conferencing application for Linux and Windows. Ekiga supports both the SIP and H.323 protocols but also supports many other high-quality audio and video codecs. Plus you can also text-chat with your contacts. Ekiga is completely free to download and use.
   http://www.gnomemeeting.org/
   Windows Download:
   Coffee Cup Live Chat is a downloadable software that you can install on your server and that allows you to chat with your website's visitors. After a visitor clicks the chat link on your site, a new window will open on his screen and will add him into the chat room: you can have a conversation with an unlimited number of people, use emoticons, and get a chat transcript sent to any participant's email automatically. Free to try, $34 to buy.
   http://www.coffeecup.com/live-chat/





3. TwitterCube
   
   TwitterCube is a web-based tool that you can use to share files via a Twitter post. After you provide your Twitter credentials, you just have to select any picture, video or document up to 10MB, click a button, and wait for all your readers/friends to get the file, which will stay online for 30 days. The service is free to use, with no sign-up needed.
   http://www.tweetcube.com/