As a sidenote, both intel and the QT folks are working on synchronizing timers in MeeGo. That is, the app can request a wakeup with specified precision (or lack thereof). Say you want your app to wake up every 10 second, but you don't care that much about exactly 10 second. So you can ask "10 seconds, give or take a few", and the kernel or qt can look for another app that has a similar requirements, and slowly move their timers closer together until they fire at the same time, effectively coalescing the wakeups of two apps into becoming a single wakeup.
Function for registering callbacks using the system-wide synchronized timers: hd_status_plugin_item_heartbeat_signal_add