Uses JavaScript. Comes with iPhone, BlackBerry & Android support. PhoneGap apps have access to geo location, vibration, accelerometer and sound.
Uses HTML extended by special tags and Ruby. Comes with iPhone, BlackBerry, Windows Mobile, Symbian & Android support. rhomobile apps have access to geo location, contacts, camera, native mapping and push SDKs.
Uses HTML, JavaScript, CSS, Python, Ruby and PHP. Titanium apps have access to UI APIs (dialogs, alerts, buttons, toolbars, navbars, menus and tabbars) and Phone APIs (geo location, accelerometer, maps, sound, database, file system and network).