I installed Flash on my box by going to
http://www.macromedia.com and clicking the download link at top and then download now.
I saved The file install_flash_player_7_linux.tar.gz to my home folder and unziped it. In the unziped folder there are two files libflashplayer.so and flashplayer.xpt simply copy them to your plugins folder for mozilla. Im running firefox the path for me was /usr/lib/firefox-1.0/plugins
you will need to do this as root.