Dash, a relatively new jailbreak tweak, switches up multitasking on your iPhone by replacing the current multitasking switcher with an elegant card like interface that you can swipe through.
If you're familiar with the way Safari already handles multiple web pages like cards you'll be right at home with Dash as the concept is very simliar. Once you've installed Dash there isn't too much to customize. Just pop into Settings and choose what gesture you'd like to use to activate Dash. If you'd like it to override the default multitasking switcher just choose double tapping the Home button to activate Dash.
Once Dash is activated you can tab from left to right through all your open apps. To close one just flick upwards and the app will close out completely. Under Settings you can customize the animations that Dash uses while in multitasking view. You can choose between animations such as Scroll, CoverFlow, Time Machine, Rotary, and Cylinder. The only other thing you can customize is what gesture will invoke Dash. In my experience the Scroll animations are the smoothest and makes closing out apps extremely fast. The other fancier animations are nice to look at but seem to slow down the entire UI of Dash quite a bit.
For those of you that have ever used webOS in the past, Dash uses the same card layout and gestures that you would have seen on phones such as the Palm Pre. If you prefer that kind of multitasking over default iOS, Dash is definitely for you.