ASP.Net Worker Process Memory Profile Tools

We have a fairly high volume ASP.Net site written in c# using MS commerce server, running in a 32-bit environment. I see the worker process up to 980 megabytes quite often. I would like to profile this process and determine where any gains could be made in code to reduce the memory foot print of this site. My question what tools have worked well for you doing this sort of thing on ASP.Net web applications?