E instead of 3G

As noted, E is EDGE, the older, slower network. Even if Settings > General > Network has Enable 3G set to ON, if no 3G signal is available the iPhone will use EDGE. If no EDGE is available, the iPhone will use the even older and even slower GPRS network (and you'll see a 'o' symbol next to the carrier name).

If you're in an area where there should be 3G coverage, you might try toggling Airplane Mode ON then OFF or reset the iPhone, either of which will force a reconnection to the the cell network. To reset the iPhone, press and hold the home and sleep/wake buttons until you see the Apple logo (ignore the slide to power off prompt).

the E stands for Edge network it bounces back and forth from edge and 3G. go to setting, general, network and then see if your 3G is on. it's common though. It's nothing to worry about.