Converting 2-AA battery Powered Devices to Lithium Power

[Metallover]

My $70 camera runs on AA batteries, and it sucks. I get about 5 minutes out of alkalines and 2 minutes off of rechargables.... I want to convert it to lithium power. What is the best way to go about this?

I'm open to life and lipo. I could use a 1p or 2p config of 1100mah LiFe cells, then I would only have to step the voltage down from 3.6-3.3v, if I even need to step it down at all.

If I went with lipos, I would have more capacity, size, shape, and mounting choices. The thing with that is I need to step the voltage all the way from 4.2-3.7v to 3v.

I plan on ordering the batteries from hobbycity with my next order. What is the best way of going about decreasing the voltage? Do I need a voltage limitor? Just a simple pot?