It is not bricked, just follow these steps and i am sure it wil start working. The same thing happened to my bro's ipod touch, and my grilfriend's iphone and i got both working doing the following:
1) Plug your iphone into the mains adapter, and leave it for an hour or so so that it is fully charged, you won't know of course, because it won't turn on, but just plug it in and leave it.
2) Once you have given it enough time you need to put your phone into recovery mode. So open itunes and plug your phone in.
3) hold the power button and home button TOGETHER for 10 secs.
4) after 10 secs release the power button and keep holding home button for a further 10 secs.
5) itunes will then recognise your device in recovery mode and ask you to restore.
Simple really, try it and let me know. the key is to let your iphone charge. if it isnt FULLY charged it won't respond, so leave it for enough time.