Hooklogger is a great tool for Symbian. I've used it a number of times to track down memory leaks. It basically replaces the epoc user library (EUSER.DLL) on the emulator. Whenever a memory allocation or de allocation occurs Hooklogger can record that event. To make things even easier to also records the a stack history at that point.
When a program closes you can check with the Hooklogger UI for any un allocated bits of memory. At this point the stack trace is really helpful since you can put each of the memory allocation events in perspective.
There is a great article on the SonyEricsson web site which documents Hooklogger, but don't worry Hooklogger can be used on any Symbian 9.1x emulator platform. I've used it while developing TextQuick amongst other things.
You can find Hooklogger to download on the Symbian web site. Hooklogger contains a number of perl scripts which effectively allow you to turn Hooklogger off and on again. There was a small error in the perl script when I downloaded it. I think it was a missing quotation mark, and a missing semi-colon. But stick with it and fix the script, the tool is really worth the effort.