Multiflow is available now in Cydia Store..
Multifl0w is an upcoming iPhone utility which lets you easily switch between backgrounded applications. Multiflow will add a nice graphical interface to the backgrounder app for iPhone.
Multifl0w will hit the Cydia Store in the next few days and it will be a great first substitute for the multitasking feature on the iPhone. Meanwhile you can have a look at the video demonstration below: