To install Sopcast on Ubuntu 11 (32 bits):
1. Open Terminal
2. Add Sopcast PPA
sudo add-apt-repository ppa:ferramroberto/sopcast
3. Update the repository
sudo apt-get update
4. Install Sopcast
sudo apt-get install sopcast-player
Now you can launch Sopcast
If you want to open the sop:// link in Firefox, please continue to read this post

