Can VFPCOM be used by a VFP MTDLL? This so that the DLL can easily return VFP cursors that have been converted into ADO recordsets (which in turn are passed back to an Active Server Page application)? For example, one question I have regards the thread-safety of VFPCOM. I would expect no problems using it with a single-threaded VFP EXE. But what happens with an MTDLL (that is invoked by a multithreaded application such as ASP)? Will VFPCOM still work in that environment?

Yes it will. There is a sync SYS function that makes sure VFPCOM only deals with on request at a time.

You might check Claude Fox's site for white papers.
http://members.cox.net/claude.fox/

There was also some good stuff down the page a bit:
http://weblogs.foxite.com/ "VFP MTDLL VFPCOM"
And here:
http://www.black-beans.com.br/artigosvfpweb.htm
This is a good paper:
http://www.calvinhsia.com/papers/AdvancedVFPServers.mht

The GLR Site has some new VFP 9 VFP Server papers too:
http://www.glrsoftware.com/Links.asp

There is a SYS function that will queue your requests to VFPCOM (i think)

* Some code from a VFP MTDLL function
....
SYS(2336,1)
WITH this 
... ask VFPCOM for something
ENDWITH 
SYS(2336,2)
.....