Photo credit: Ivan Stevanovic

1. AirTalkr: Connect to multiple IM networks and access all major Web 2.0 services from one place
2. Yugma Skype Free screensharing solution allows you to share your desktop with everyone in your Skype contact list
3. PikiWiki: Drag and drop files on a web-page, and invite other people to view or add new files
4. MSN2Go: Free Java-based MSN Messenger client allows you to connect to the popular IM network anywhere

1. AirTalkr
   
   AirTalkr is both a downloadable and web-based application that allows you to connect to multiple instant messaging networks such as MSN, Yahoo!, GTalk, AOL and ICQ, and also to access various Web 2.0 services like Flickr, YouTube, Twitter, Myspace and more. Just sign up to AirTalkr with a free and simple registration, and then you will be able to add all of your services' logins so that you have to remember just one of them. Free.
   http://airtalkr.com/





2. Yugma Skype
   
   Yugma Skype Edition is a free screen sharing solution that builds upon Skype's offering by adding screen sharing. Once Yugma Skype Edition in installed, you simply invite a friend or colleague from your existing Skype contact list, which is directly accessible from within Yugma and you are set to go. The free version allows you to invite up to ten people. Other versions available here.
   https://www.yugma.com/yugmaskype/





3. PikiWiki
   
   PikiWiki is a browser-based software that enables you to use any browser as a blank sheet of web paper. You can create a simple web-page where you can drag and drop your own video clips, photos from your computer, pdf docs, mp3 files, powerpoint slides, voices, text, website links, or anything you want and anybody can be invited, and access that page to view or modify it adding new things. No registration is needed and it is free to use.
   http://pikiwiki.com/





4. MSN2Go
   
   MSN2Go is a free Java-based MSN service that allows you to chat with your friends from work, school, libraries, and anywhere the official MSN Messenger is not available. There's no software to install and it works on any Java-enabled browser, even behind firewalls and proxy servers. Free.