I'll probably get into trouble for saying this but I simply use Symantec's PortablePGP which will work on any OS including Ubuntu provided you have the "Java Runtime Environment" installed. The reason this option isn't favoured by those who are very keen on protecting their privacy is because the source code isn't available for peer review and Symantec don't have the best reputation when it comes to computer security.To answer your question, as hatedpatriot says it's not very easy any more to find a good GUI for GPG in newer versions of Ubuntu. My own solution was to install Mozilla Thunderbird from the software centre then install the "Enigmail" plugin (http://enigmail.mozdev.org/home/index.php.html) which allows you to use PGP to read and encode messages, as well as add/remove keys. This is not the most elegant solution but will do at a pinch, I'm sure hatedpatriot's script is much quicker to use! :-)V.