I ended up purchasing a dedicated wireless IP camera for this purpose, for $50 on sale; the Foscam C1:http://www.amazon.co...ection/dp/B00VN0G8GQ
The setup was extremely frustrating, but it does seem to work reasonably well, and will send emails with photos when motion is detected.
The main key thing is that it needs NO pc running at all -- it is a self contained thing as long as it can connect to the wireless network, and as i described above, it will serve it's purpose even if it's destroyed soon after alerting -- as long as it has had a chance to send email beforehand.
So the nice part is I can just plug it in when needed and let it do it's thing, and it will send emails with photos if motion is detected.
I may still write a little piece of freeware to do the same thing using a webcam.. something with very few options and features dedicated to this task.