[bombs]

You do. The signal strength bars are to the left of the carrier name, while the connection type (EDGE, 3G, WiFi) icon is the right.

The WiFi icon (which acts as a signal strength indicator for WiFi connections) unfortunately does hide the cellular data indicator, which shows whether you're connected to EDGE or 3G.

[bmalicoat]

What I mean is you could have full voice signal with no data signal and not know it if you are connected to wifi too. Most areas have at least GPRS, but you can still find some towers that are voice only. Because of this you really don't have an indication of your cellular data. You can assume you have it, which is true most of the time, but you can't know for sure.