They never made any difference for me either. I find the 2G to have very low volume, but 3G and 3GS are much better. Just clean the speaker and you should see a difference.
a Amplifier I did also buy AirCurve from Griffin http://www.griffintechnology.com/products/aircurve it's a dock it does work really well! don't see any way to do it software wise. I have tried booster as well (fail!) maybe 4G will have a better Speaker as well!
BTW -aggie- I know you are not a fan of me and my post! Some of us don't have all the same skills as others. My post are meant to help as I am honestly trying to help you! Any way have a good day!