i have a n900 got it late in dec battery life was good but not great i had facebook widget on ,weather,email,3g,msn and auto connect on wifi however 3 days ago battery developed a fault only last 5 hours max with only 1 phone call of 3 mins ,no txt etc i turned all stuff of even ran on 2g.The battery life on this is unbearable has anyone else experienced this .

I know this is going to sound daft but it has worked with a few odd problems. Try shutting down and pulling the battery for a bit then replace the battery and reboot. See how the battery lasts after a full charge then.

Have you been playing in Extras-Devel? It might be an app with cpu consuming problems...
Have you bought a new Case? It happened to my before, that the magnet will cause the screen to be on and consume plenty battery.