Installing Flash can be a pain, especially if you have a 64-bit operating system. However, we can use workarounds provided by the Linux community to avoid the common problems. If you are using Ubuntu, Flash comes with the restricted extras package which can be installed by typing the following into your terminal:
sudo apt-get install ubuntu-restricted-extras
If you do not want to get all of the restricted extras you can instead just download Flash by typing the following:
sudo apt-get install flashplugin-nonfree
You can also go to the main Flash website if for some reason apt is not working, or you are using a Debian system. For other Linux-based operating systems you may need to go to the download site mentioned before, download the .tar.gz and compile it yourself. They do have RPM and YUM images as well if your Linux distribution supports either of these. The website does provide downloads compatible with most major distributions.
If you are unfamiliar with package management systems on Linux a read through of this article will help you understand what they are, and how they work.
There are also many open source versions of Flash player but you get the most quality and ease of use by using Adobe's own player. Gnash and other open versions generally do not provide the enhanced power we need to watch videos on Iplayer.