As discovered by Todd Carter there is a memory leak in SharePoint 2007. He has outlined the details as well as a work around to the fix the memory leak.
I decided to do some testing with it, however, when I compiled the dll, placed it into the GAC, and changed my global.asax file, I started getting this error: “Could not load file or assembly ‘[Assembly Name]’ or one of its dependencies. The system cannot find the file specified.”
After digging into this error for a while I discovered my problem. This may be fairly obvious to developers out there :), but coming at this from more of a SharePoint administrator type roll, I missed this one step that isn’t outlined in the steps provided by Todd.
After deploying your dll to the GAC, you need to open up your web.config and place
<add assembly="[Assembly Name], Version=[Version Number], Culture=neutral, PublicKeyToken=[Public Key Token]" />
in the web.config file of the web application you wish to apply your fix to. This line should be added between <assemblies> and </assemblies> in the web.config file.
All of the information: Assembly Name, Version Number and the Public Key Token can be found by right clicking on your dll in the GAC and viewing the properties of the dll.
Once I added the assembly to my web.config for the web applications I was trying to apply the fix to, everything worked as expected.