I am new to Android SDK and AVDs and I was wondering if there is anyway I can enable the cellular network on an Android AVD and make for example phone calls.
You can call between AVD's. Run 2 AVD, each will have diffrent number - it is placed on window title bar, example 5558. Call from one to other using this numbers. You can also text ;]
In your AVD you simply cannot use real celluar network because your PC/Mac do not have built-in GSM modem (even if, AVD is not supporting this kind of feature).