Flash player, useful for watching videos online, can be downloaded and installed as follows, on Ubuntu Karmic.
1. Download the plugin from here.
2. Save the file. I saved it in my 'Setup_Files' directory.
3. Open the terminal, and cd to the directory where you have saved your file.
varsha@varsha-laptop:~$ cd /home/varsha/Setup_Files
4. Uncompress the file.
varsha@varsha-laptop:~/Setup_Files$ sudo tar -xzf install_flash_player_10_linux.tar.gz
5. Copy the extracted file to the 'Mozilla plugins' directory.
varsha@varsha-laptop:~/Setup_Files$ sudo cp libflashplayer.so /usr/lib/mozilla/plugins/
6. Delete the tar.gz and the extracted file, if you want to, using the rm command.
varsha@varsha-laptop:~/Setup_Files$ rm libflashplayer.so