Isolating memory leaks?

[michaelsanford]

I'm using iPulse to monitor my system and I noticed something strange (which I check out with top). I've got 786 physical.

I have only Chimera, MSN, and iPulse open, and according to iPulse I'm using 41% of my memory. Top says something even worse.

Processes:  59 total, 3 running, 56 sleeping... 171 threads            13:42:30
Load Avg:  0.94, 0.86, 0.84     CPU usage:  36.9% user, 17.7% sys, 45.4% idle
SharedLibs: num =  120, resident = 27.1M code, 1.59M data, 7.45M LinkEdit
MemRegions: num = 4549, resident =  111M + 10.7M private, 78.1M shared
PhysMem:  73.6M wired,  239M active,  398M inactive,  711M used, 57.4M free
VM: 2.54G + 49.8M   27961(0) pageins, 2391(0) pageouts

Now, when I boot, I use only 21% (according to iPulse). I've recently used RealPlayer, DreamWeaver MX, GraphicConverted and Amadeus II (which uses a ton of ram when active).

How can I figure out which apps are leaking? I assume something's leaking, since at this state, wouldn't the RAM usage return to the same state it would be at if I'd just booted and started only these apps (which should be around, maybe, 30%).

And, according to top, why am I using 711 megs of RAM? Is that shared ram that's inactive, and releaseable to an new app that asks for it? (I'm not very familiar with OS X's memory-allocation model, as you can tell)

Thanks for an ideas