Finding memory leaks in Windows

I was trying to figure out where a memory leak was coming from on Windows, and didn't have the luxury of using Purify, and this really helped:

http://blogs.msdn.com/greggm/archive/2004/02/12/72209.aspx

Essentially, VirtualAlloc is the equivalent of sbrk in other OS's, and allocates virtual pages to the process. If you can find out what's calling that all the time, you're likely to discover what's allocating memory.