First off, if this is anywhere else then I apologise for posting it again, but I've just found it so am a bit over excitable...
Second, I have found it on my Curve 9300, but it might be on the other models that have the keyboards so I've not put it in the Curve section.
Anyway, memory usage.
Go onto OPTIONS....DEVICE.....APPLICATIONS. This brings you to a list of what is installed on your phone.
Once in applications scroll SIDEWAYS....and there are a few pages that show the memory. The first couple show combines apps.
But the interesting bit is if you keep scrolling and youi get to a page that shows what each app/thing/phone etc is using and what is running. You can then scroll down the list of apps etc on your phone and see what is running, what is using memory and how much it is using etc.
Its brilliant...
Ang x