CamTwist for Mac

CamTwist for Mac is a free video app that allows you to spice up your chats with all sorts of original and special effects. CamTwist is a little difficult to set up, but once installed it works with most video chat services, such as Skype, Yahoo! Messenger and uStream. You can also stream from the desktop, or Flickr, for example.

CamTwist includes a Studio section, which will allow you to do a bit of live mixing, like adding overlays, switching cameras, or creating a live slideshow. The more technically gifted can also create their own special effects! This, coupled with the more than 50 effects available by default, let you really get creative without having to spend any money. If you like tweaking around with your Mac, you'll also be glad to know that CamTwist offers AppleScript support, which opens the application up to all sorts of customization.

Despite being a little complicated at the beginning, CamTwist is a very good free tool to add fun effects to your video chats.