I was looking for an easier way to make more room for applications when I found this excellent howto. You will need to setup your phone to store by default in the external storage, and then suddenly almost any installed application can be moved to the external storage, and the newly installed applications will go there by default.
I'll describe the process that I made in order to configure my phone. I used a laptop with an Ubuntu Linux distribution installed.
First, we need to install the Android SDK Manager in the computer. In Ubuntu, we can use a PPA repository:
sudo add-apt-repository ppa:upubuntu-com/sdk sudo apt-get update sudo apt-get install ia32-libs android-sdk
Now we can open the Android SDK Manager and install the SDK Platform-Tools if we don't already have it.
Then, we need to connect our phone to one of the laptop's USB. We allow USB debugging on our phone in Setup > Applications > Development.
Finally, we reconfigure the storage defaults:
cd ~/android-sdk-linux/platform-tools ./adb kill-server sudo ./adb start-server ./adb devices ./adb shell pm setInstallLocation 2