Hey, I just thought I would pass on this little tip that an O2 salesperson told me over the phone this afternoon. Basically, you get better reception if you choose "O2 - UK" specifically as your carrier, rather than letting the iPhone choose a carrier automatically. Go into Settings, choose "Carrier" and select "O2 - UK" rather than "Automatic". I am now getting five bars around my house when previously I was only getting one or two. I have no idea whether this is a well-known thing but I thought I would mention it in case it helps other people.