As you know, SeaMonkey version supplied with Ubuntu 9.10 is still v1.1.17 which is outdated.
To install SeaMonkey 2.0.1 simply add this line to your system's software sources:
using the menu: System > Administration > Software Sources > Third-Party Software
or by editing this file: /etc/apt/sources.list
previous Ubuntu versions:
deb http://ppa.launchpad.net/joe-nationnet/ppa-seamonkey2/ubuntu karmic main
deb-src http://ppa.launchpad.net/joe-nationnet/ppa-seamonkey2/ubuntu karmic main
Then install SeaMonkey 2 by typing these commands in a terminal:
sudo apt-get update
sudo apt-get install seamonkey-2.0
SeaMonkey 2 will install alongside SeaMonkey 1.x and will import all your e-mails, passwords, bookmarks and preferences and it works on both 32 and 64-bit systems.
By default, a shortcut to the e-mail client won't be created, you can create a new one (or edit the one used for SM1) and point it to the command: seamonkey-2.0 -mail
Thanks to Joe Lesko for making it possible!
And if you want to find back the good old Netscape look removed from SM 2.0: Install the Classic Default theme: https://addons.mozilla.org/fr/seamonkey/addon/46108 (attention, this theme is still in beta state).