How to install and configure the Thunderbird and add lightning extention to the calender ?
Ans :
Thunderbird is an excelent e-mail client known in open source world other popular e-mail client is evolution. As of this writing TB3 is still in beta phase so we will see how to install Thunderbird 2.0.0.23 on
Ubuntu 9.10.

Step1 : Edit the source list to point the mozilla reposatory and add the below mention reposatories at the end of the file.
#gedit /etc/apt/sources.list
deb http://ppa.launchpad.net/ubuntu-mozilla-daily/ppa/ubuntu karmic main
deb-src http://ppa.launchpad.net/ubuntu-mozilla-daily/ppa/ubuntu karmic main
save and exit the file

Step2 : Update the reposatory list, that your system knows from where we should download thunderbird and install it
#apt-get update

Step3 : Now install mozilla with apt-get command
#apt-get install mozilla-thunderbird
Reading package lists. Done
Building dependency tree
Reading state information. Done

The following extra packages will be installed:
thunderbird
Suggested packages:
thunderbird-gnome-support


The following NEW packages will be installed:
mozilla-thunderbird thunderbird

0 upgraded, 2 newly installed, 0 to remove and 192 not upgraded.
Need to get 12.2MB of archives.
After this operation, 36.3MB of additional disk space will be used.
Do you want to continue [Y/n]? y

Get : 1 http://archive.ubuntu.com karmic/main thunderbird 2.0.0.23+build1+nobinonly-0ubuntu1 [12.1MB]

Get : 2 http://archive.ubuntu.com karmic/main mozilla-thunderbird 2.0.0.23+build1+nobinonly-0ubuntu1 [62.0kB]Fetched 12.2MB in 1min 52s (108kB/s)
Selecting previously deselected package thunderbird.
(Reading database … 114241 files and directories currently installed.)
Unpacking thunderbird (from …/thunderbird_2.0.0.23+build1+nobinonly-0ubuntu1_i386.deb) …
Selecting previously deselected package mozilla-thunderbird.
Unpacking mozilla-thunderbird (from …/mozilla-thunderbird_2.0.0.23+build1+nobinonly-0ubuntu1_all.deb) …
Processing triggers for man-db …
Processing triggers for desktop-file-utils …
Setting up thunderbird (2.0.0.23+build1+nobinonly-0ubuntu1) …
Setting up mozilla-thunderbird (2.0.0.23+build1+nobinonly-0ubuntu1) …
Processing triggers for libc-bin …
ldconfig deferred processing now taking place

Step4 : To access newly installed Thunderbird go to
Applications–> Internet –> Mozilla thunderbird mail.

Step5 : Now configure and add the lightning extention for getting calender.