App to extend battery life? What?
Hmm..I would say pay attention to how you use it. Try to avoid many applications that keep connection alive (facebook widget, messaging protocols) when you do not use it.

What webpages are slow? On what connection you are? IIRC Opera is in testing
http://maemo.org/packages/view/opera-mobile/
So that´s one potential tryout for browser, but still microb is quite fast.