I am working with a group who already has several WSS sites. They want
to create a team site, and I think it's most appropriate to have the
other sites as sub-sites to their team site. Is there an easy way to
do this? Can you move a site into another site (like moving a folder
into another folder)?

I assume nothing can be that simple in SharePoint, but I thought I'd
ask! I did something like this once before, but I wound up creating a
sub-site, then taking all of the documents and moving them out of the
original site into the new sub-site, and recreating some of the lists.
I'd prefer a simpler option if one exists!