out of memory

Hi,
I am getting this out of memory error on my asp website running on IIS.
We tried to move the application to 3 different servers and same error
happens in all the 3 (windows 2000 and windows 2003). We have 4GB of RAM on
all these boxes. Following are the details I could find out from the IIS
dianostic tools and the windows task manager:
1. The out of ememory happens even when the IIS w3wp process reaches 350mb
(which is less than 1/8th of total memory).
2. I took the IIS memory dumbs and tried to analyze(I could not understand
many fo the details). I noticed that the rtemplates cached (350 templates)
only takes about 106mb. So it does not look like any template cache size
issue but not sure.
3. If there is a memeory leak due to unreleased objects, should the IIS
process memory peak to its capacity. For us, the out of meemory happens when
the IIS process memory shows only less than 350mb in the windows task maanger.

once we restart the IIS, the issue happens after 6-8 hours.

Can anybody help me?

Thanks,

Thomson.