These steps should work to install the latest version of the FCE UltraX (FCEUX) NES/Famicom emulator in Ubuntu.
1. Install necessary dependencies.
2. Open a terminal (Applications... Accessories... Terminal) and obtain source from subversion.Code:sudo apt-get install scons libsdl1.2-dev subversion libgtk2.0-dev
3. Change directory into the fceultra folder.Code:svn checkout http://svn.code.sf.net/p/fceultra/code/fceu/trunk fceultra
4. Build and install fceux.Code:cd fceultra/
And that's it! You can also grab an older version of fceux from the Ubuntu repositories, but the latest and greatest can be obtained and compiled from subversion.Code:sudo scons install
If you would like to contribute, or run into any issues, feel free to join us in #fceu on irc.freenode.com. You can also file bugs to our tracker (http://sourceforge.net/p/fceultra/bugs/). Please note that you may not receive an immediate response in IRC -- idling is key.