Has anyone out there worked with file associations via an MDI interface? If so, you're my hero

The trouble is that, with an MDI, you only want one instance of your program running. Thus, when Joe double click on a file associated with your program, any second copies of the program that are started need to communicate to the first instance the name of the file that the user is attempting to open, and then that second instance needs to close itself.

I've found a project over at vbAccelerator (I think?) that does this, but the description is rather over my head and I haven't been able to make it work. Plus, he uses some annoying timer DLL that I'd rather stay away from if possible.

All I'm looking for here is a straightforward, not overcomplicated way of implementing file associations with an MDI.

SOMEONE out there HAS to have experience with this

Daniel