Here's a list of all the new features and some of the improvements you'll find in Skype version 18.104.22.168 for Linux:
* High Quality Video support.
* Skype's SILK audio codec.
* Pulse Audio support
* SMS sending support.
* Chat messages editing/removing support.
* Typing notification in chat.
* Chat picture support (add/change/remove) for group conversations.
* Mood messages are visible in contact list and tooltip.
* Video/Mobile icons are visible in contact list.
* Bookmarked Chats are visible in contact list.
* Contact labels/tags.
* Right-clicking on the user name in the chat will open contact menu.
improvement: A day divider is added to the chat. Timestamps are shorter for old messages.
* Clickable links in mood message.
* Enlarged tray icon, also showing number of missed events.
* Flag button is replaced by button showing number of missed events.
* Updated ALSA device detection, nicer to USB headsets.
Install Skype 2.1 beta in Ubuntu
First you need to remove the existing version of skype using the following command
sudo apt-get autoremove skype skype-common
Download .deb package from here and install the downloaded package using the following command
sudo dpkg -i skype-ubuntu-intrepid_22.214.171.124-1_i386.deb