UPDATE and A QUESTION:
It turns out the 40D was beyond what I could afford. But I finally bit the bullet and bought a new Canon EOS XTi 400D. My T-Ring, T-Adapter, and remote shutter control should be here this week some time.
I'm really excited!!
The Mac software that came with the camera does let me control it from my laptop, but not in Bulb mode.
But that's OK. I plan on giving it a go by holding the shutter open manually and will probably purchase the TC-80N3 in a month or 2.
Have I said how excited I am?!!
Anyway, I have a question. I notice on many DSO photos the photographers will say, "auto guided" or "unguided". I'm not sure what unguided means? Can you take a long exposure "unguided"?
Thanks to everyone for their help and suggestions!