Well i think the someone mentioned that the multitasking on Iphone is not true multasking since currently any app that you open when pressed the HOME key it closes but shows up in the multitasking tab..a multitasking app will continue where it was stopped but on the Iphone it restarts all over again..i tested this with games and it restarts all over...

and to be honest i dont see it having an adverse effect on the battery life with the so called multitasked app minimized might i say iOS4 has improved the battery life by a bit..my batt levels are at 42% with a few calls and sms'es and short games....and yet with these apps coming up on the multitasking tan

I think for the moment the multitasking is just to show what are the apps that you've opened recently when you invoke it it restarts..does it mean it runs in the background if it does it should continue from the point it was stopped but not with this one...so i can that you can give yourselves a break from double pressing the HOME button twice each time to close the app..yeah there will be a clutter of apps but i guess its just to show what apps you have used...and im only gonna clear it once a day    since as i mentioned earlier, it doesnt seem to affect the battery life or the speed of processing ...well of course if you do have OCD then by all means go ahead and close the app each time by invoking the Home button... oh i have an Iphone 16GB 3GS btw..

and just a little bit of disclamer Ive come to this conclusion based on my test that ive done throughout today and results may or not vary if you decide to do what i did