Sending notifications from the desktop to an android device I'd like to be able to be able to send alert from my PC to my phone, preferably via wifi.
The only related app I found was Android Notifier, but it does the other way: android to PC.
You should check out Google's Cloud To Device Messaging (C2DM) framework. If you just want to send stuff from your browser to your phone try Chrome to Phone (it's a kind of reference implementation of the C2DM framework).

Good luck!