I have to admit I was annoyed when I read that developping an app for your N900 was only possible using a Debian installation. I personally am using a Mac and I did not want to start installing Ubuntu or any other OS on my machine, virtualised or not. But then I came accross MADDE (Maemo Application Development and Debugging Environment).
MADDE is a technology preview but allows someone that is using a Mac or Windows computer to install a development and debugging environment which lets them write, compile and package a C++ or Qt application for Maemo devices.
Installing it was really easy, just follow the guide on the Maemo wiki. The only thing I did that was different from the guide was the USB networking (could not get it to work on the Mac-side). Instead, I just used my N900’s WiFi instead of setting up an extra connection on it. It also works that way. I was really happy to get my “Hello World” screen to work. Now the serious part can start, I’ll have to dive back to C++ first 
Right now MADDE only supports up to Qt 4.5, there is a workaround to get Qt 4.6 to work but I think I’ll just stick with 4.5 while waiting for a MADDE update.
Somehow I didn’t know this one, thx for sharing!
-S