According to a lecturer at uni, mobile devices use more power when they have to try and hold a connection (wifi or mobile network) that is further away. Apparently moving your router closer will allow the device to conserve energy by allowing it to power down it's radio because it's not having to broadcast it's signal as far. This also extends to cell towers - it seems living a long way away from one will make your phone work harder to keep a 3G/EDGE/GPRS signal and thus wastes battery. I'm inclined to take his word for it, what with a PhD under his belt on the subject! So... heres a new battery saving tip for ya...... MOVE HOUSE! Nah but seriously, I think this holds some truth, when I was in London over the summer I swear my battery used to die so much quicker because it kept having to try desperately to hold onto weak signals being blocked by all the built up areas. Not a lot anyone can do about it but it might go some way to explaining the differences in battery life people are reporting.