I have an iPhone 4 with iOS 4.0.1. to close an app from the multitasking/task switcher, you have to click and hold it all icons start wiggling. then click the red icon on the top right corner.

is it possible to implement it in a way that if I want to close an app in the task switcher, i just drag it up and it will be closed? just like backgrouder and Palm Pre works.

I hope this is an easy thing to implement.

Soon enough there should be two programs that do this -- multifl0w is an expose like task switcher, and ProSwitcher is almost an exact duplicate of the Palm style 'pages' interface.

Neither are presently available for iOS 4.0 right now, but based on a few tweets from @comex and the crew, I'd expect to see them released in the very near future.