Last night I installed a Pear channel on my Aspire One so thought about sharing the installation process with you. You might have a look at Greg Beaver’s howto, three years old but it’s the official installation, add it to your bookmarks anyway.
PearChannel-Admin
First if you don’t have a LAMP already run

sudo tasksel install lamp-server

Then follow the installation process, which documented here.
Then we need to install PEAR iself :

sudo apt-get install php-pear

You can make sure that pear is correctly installed by running:

pear -V

I recommend you to use ubuntu pear package instead of downloading go-pear.phar and install it manually.

Now you can get the Chiara_PEAR_Server

sudo pear channel-discover pear.chiaraquartet.net
sudo pear install chiara/Chiara_PEAR_Server

If this doesn’t work for you, read returned message by pear and you will probably have to run :

sudo pear install --alldeps channel://pear.chiaraquartet.net/Chiara_PEAR_Server-0.20.0

Here I had to install all required packages one by one manually using everytime “sudo pear install –alldeps channel://pear.php.net/Package_name-version”. Just make sure you have MDB2_Driver_mysql or MDB2_Driver_mysqli drivers installed. After installing all dependencies get back to previous line and run it again to install Chiara_PEAR_Server.
And before going to next step you need to create “pear” user in mysql and give it full permission, or create “pear” database and a new user with full privilege on it.
Finally read instructions and if everything is okay you should be able to run :

sudo pear run-scripts chiara/Chiara_PEAR_Server

Enter an admin handle (for example hatem) and admin password, channel name (for example hatemnetbook or pear.yourdomain.org), database information, and finally your www path (for example /var/www).
Now you can point your browser to http://hostname/admin.php and you will get your new channel administration login.
PearChannel-Login
In case you want to install the chiara web frontend for endusers for a public projects :

sudo pear install channel://pear.chiaraquartet.net/chiara/Chiara_PEAR_Server_Web 0.4.5

You can test your new channel locally or remotely using et voila !

sudo pear channel-discover localhostname
sudo pear upgrade localhostname/Foo_Bar

Just note that I have installed here the latest Chiara_PEAR_Server 0.20.0 (beta) and Chiara_PEAR_Server_Web 0.4.5 (alpha), you may find more information on latest package update at http://pear.chiaraquartet.net/.