Hiyah all, Here are a couple of things you can do to slow down battry drain, Not all "tricks" will work for everyone, it depends on what you mainly use your phone for, So have a read and remember you can try them all and if they dont suit your needs its nothing permenant just follow the steps and change it back no harm done.
1: WIFI, once we've established a connection via wifi, press menu > tools >wlan > options > EXIT > back > web. This stops the phone continuesly scanning for wifi while your on the net
2: 3G, If your not a regular user of 3G then disconect it, as its constantly scanning. menu > tools > settings > phone > network > network mode. Set to gsm only.
3: WIFI, This seriously reduces power drain, however i've read it could affect recieving weaker wifi signels but if your not to far away its fine, try it, It hasnt affected my wifi usage, i can still connect to my neighbours wifi

Your wlan uses battry power even when its not activated, by changing the t.x. power level you stop this or at least greatly reduce it. Here's how: menu>tools>settings>connection>wireless lan>options>advanced settings>YES> down to TX power level>options>change>4mW>ok> scroll down to power saving>options>change>enabled>ok> all the way back. Done
4: press and hold down the menu key, that shows you what apps you have running, shut down any thing else but standby unless your actually using it.
well i hope they help, i always follow No. 1 and have my phone set for 2+3 the only difference is my battry lasts longer

PLEASE feel free to leave any other, hints, tricks or cheats for battry saving, and post any comments you may have on how they work for you.
REPLACEMENT BATTERES ARN'T CHEAP. LETTING YOUR BATTRY RUN OUT COMPLETELY AND GIVING IT A SOLID 12 HOUR CHARGE WHEN TURNED OFF JUST ONCE A MONTH CAN DOUBLE ITS LIFE EXPECTANCY AND STOP IT RUNNIG OUT SO FAST.
SIMON.