Photo credit: Petrol

1. Mikogo: Free screen sharing and remote control solution for Windows
2. File Dropper: Share any file up to 5GB without any registration
3. Hello: Picasa plug-in allows you to chat and share any picture with your friends
4. ADPhone: VoIP software allows you to have free PC-to-PC calls

1. Mikogo
   
   Mikogo is a free screen sharing and remote control software for Windows. After you download the small setup file, you can register and create as many meetings as you want: you can then invite people by giving them the meeting ID which they'll have to paste on the Mikogo homepage in order to join the session. The main features are remote control for any participant, file sharing, presenter switcher, and application selection. Free to download and use.
   http://www.mikogo.com/





2. File Dropper
   
   File Dropper is an online file hosting website that you can use to send large files with anyone. With no registration you can upload any file up to 5GB and, after the upload progress bar has finished, you will be given a sharing link for other people to get the file. Apart from the basic free version, other paid versions are available for password-protected sharing and up to 25GB of space per file. Free to use.
   http://www.filedropper.com/





3. Hello
   
   Hello is an addition for the popular Google's picture management software Picasa, that adds a text chat and the possibility to send pictures to your friends. After you install it, you will notice a new friends lists, from which you can open conversation windows: you can then start chatting with the other person, and share any picture you have in your library by clicking a button, no matter how big it is. Hello is free to download and use.
   http://www.hello.com/





4. ADPhone
   
   ADPhone is a free VoIP application that lets have free voice conferences between PCs, but also call normal landlines and mobile numbers. You can register to the service for free and download the client to start calling other ADPhones users for free. Plus, the first two minutes of landline calls are free (up to 30 minutes per day), after which you will have to pay very low rates for both landline and mobile calls. Free.
   http://www.adphone.com/