The following has been tested on ubuntu precise.
sudo apt-get install anyremote
Download the android client from here and install it on your android device (you may need to enable unknown sources in the settings).
Now run this on your PC:
anyremote -f /usr/share/anyremote/cfg-data/Server-mode/smplayer.cfg -s socket:5197
And now run on your android device anyRemote. Press the menu button and select Search. Select TCP/IP. Select the connection with the IP of your PC. That’s it, now you’ll see a screen with some controls.
There’s a gui interface, ganyremote, but either I don’t know how to configure or it just doesn’t work.
More info: http://anyremote.sourceforge.net
Edit: in order to use ganyremote in ubuntu precise is necessary to update it:
sudo add-apt-repository ppa:anyremote/ppa sudo apt-get update sudo apt-get install ganyremote