The Telegram WebApp is available for Ubuntu 14.04 and 13.10 in a PPA. Add the PPA and install it using the following commands:
sudo add-apt-repository ppa:costales/unity-webapps-telegramsudo apt-get updatesudo apt-get install unity-webapps-telegramOnce installed, launch Telegram from Dash.
Note that to use Telegram, you must firstly install it on your mobile device.
To grab the source code, report bugs, etc., see the Unity Telegram WebApp Launchpad page.