It is only for jailbroken iPhones, but it is AWESOME. It is called ProSwitcher is in currently in Beta, but there isn't many bugs in it though. It will be opensource and FREE. You can download the Beta at this repo: h ttp://booleanmagic.com/repo
Any questions, feel free to ask.
this program is awesome! i was using another multitasking program called Kiruki (forgive the spelling) and it was ok . . but this is very intuitive and easy to use (plus some better eye candy!)