IS a heart monitor worth investing for training? I dont race but want to get my fitness levels up and shift some blubber.

Whats a good one to get? I have an Android phone and endomondo pro which i believe can sync with a monitor but which one?

Yes. no idea what syncs with phones. Plenty out there that work great otherwise: polar etc.

Polar have a Bluetooth one that works with sportstracker pro.

yes iv really noticed the diffrence in my cardio ability sins working in the correct hr zones mine was only £15 from lloyds chemist and douse all thats needed including zone managment for age range and zone alarms aswell as basic clock/alarm/stopwatch and backlight.