yeah Battery Saver DX PRO is nice too. but i tried One Power Guard by XDA programmers. its good too. but i think install Battery Saver such a eat on battery. it will not save your batter instead it will eat yours
Some users just use apps that can control processor speed. The lower the the speed of the processor, the more battery you save. Of course the performance slows down depending on the speed you set. I think the proper term is underclocking.