In my previous post I documented a bug in SharePoint where a memory leak can greatly impact that amount of memory you SharePoint WFE will use during the normal processing of web request. The SharePoint PG just recently released the 2010 April CU for WSS 3.0 and MOSS 2007. It requires you have Service Pack 2 before installing these cumulative updates but I can tell you that is something you want to invest in.
WSS 3.0
Main KB: http://support.microsoft.com/kb/981043
Download Link: Download April 2010 Server-Package for WSS (981043)
MOSS 2007
Main KB: http://support.microsoft.com/kb/982741
Download Link: Download April 2010 Server-Package for MOSS 2007 (981042)
If you dig into the description of what has been fixed in the CUs you will come across this KB which has this little blurb regarding the Sasquatch.
A memory leak may cause the application pool to recycle the AppDomain because many instances of the SPHttpApplication reach memory limits.
I cannot stress enough how much everyone running SharePoint 2007 needs to apply this fix.