Anyone? It'd be really cool to have, but I'm just afraid that as it's a Mac-specific app it might hold a Mac virus or something... Am I being stupid?
Stupid not really, there are no Mac Virii (Virii by definition can self replicate [without having to type in the admin password constantly] itself which it can't do in the OS X environment) Trojan's etc, yah, those exist (heck I'll write one for yah if you'd like) but your not being stupid, just cautious which is good.
But to calm your nerves, Darwiin Remote has been around for a long time and has been used for just as long (google will pop up several hundred hits with darwiin remote in it showing the usage and even youtube videos).
I have used it. Sourceforge (granted everyone can put up fake stuff) is about as reliable as a site claiming to be the real developers site. That being said, it's relatively safe. Knowing and have used Darwiin remote that looks like the real deal, their old blog site hasn't been updated in a while and if it has, I can't read the text.