Ekiga is an open-source VoIP softphone app that includes the functionalities of a voice softphone, video conferencing tool and instant messaging tool. It is available for Windows and Linux, is completely free and is simple to use. Though it does not come with a ton of features, it offers user-friendliness and seamless SIP communication.<p>Mikogo has three plans, one of which is fully free. It is intended for non-commercial use. So if you are organizing webinars for your business, you need to look at the other alternatives. With the free plan, you get all the webinar features, including desktop sharing, recording, whiteboard etc., and have up to 25 attendees per webinar.</p>This is a very simple tool, with not many features, but with one that is useful in meetings – screen sharing. It also offers the possibility of file sharing and access using mobile phones running iOS and Android. A meeting can have up to as many as 250 attendees for free. The paid version gives more features.This service looks generous and gives many things for free, but with advertisement. If you are OK with ads on your screen and on that of your attendees, then you can have up to 200 attendees per meeting, conferencing calling, screen sharing, video broadcasting, recording and some other features for free.This is open source software that is free and that allows you to very easily and instantly set up conference calls, using either voice or video. There is no limitation on the usage or on the number of persons participating in a meeting. It offers the possibility to share desktop, share documents on a white board and record the meetings. It requires you to download and install a small package on your server before using.This tool is free with all the features for up to only 10 participants. The main feature is screen sharing, with other features like Skype audio, recording, meeting analytics, and registration.Likewise, you can use Vyew and its features for free with up to 10 participants per meeting. You have to bear up with ads unless you upgrade to paid premium version. Vyew is browser-based so there is no need for participants to download and install software before participating in webinars and meetings.Lync is Microsoft’s unified communications tool with IM and presence management including collaboration features. Lync is not free, as nothing really is with Microsoft, but you can have a 6 months trial period, which is a lot of time. You can download and use the Lync Server 2013 software and use it with Office.