If you are looking for a secure, very easy to configure and use, remote desktop app (and I am happy to report it works well with Linux), check out TeamViewer. If you don't mind the app reminding you to upgrade it--and the lack of a few features--it is completely free. You can grab everything you need here (DLs available for Mac, PC, and Linux), and the app store link above. The config for Ubuntu geeks is pretty simple (download the debian package, run the desktop app, and perform similar actions on iPhone to connect).
