There's not much to QuickTaskman - and yes, I'm sure there are other utilities which offer this, so please don't write in - but here it is in place, anyway:
QuickTaskman is crying out to be on each homescreen if you make a lot of use of the Symbian multitasking carousel. It's true that many larger utilities (not least SnakeSoft's own AndroTaskman) also incorporate this function, but why install something larger and more complicated if you don't have to?
You can download QuickTaskman for free here in the Nokia Store.