Finding Memory leaks

Which tool do you use to find them?

CLRProfiler -- look for that title in Microsoft downloads. There is also an overview of memory management investigation in one of the recent MSDN magazines.

Depends on what language you are asking about.

For C++, I use the debugger. I have code, that on shut down, tells me the memory location of a memory leak.
For a really pesky memory leak, I use windbg and look through the memory heap and at the call stack that created each one.

Read Rico Mariani's Tracking down managed memory leaks (how to find a GC leak)

u can use .Netmemprofiler http://www.scitech.se/memprofiler/Default.htm its pretty good   

Thank you very much