Use these WebWise Step-by-Step guides to help you download popular plug-ins:
Plug-in
What it does
Real Player
Popular sound and video player - used on BBCi
Flash Player
Used for animations and games
Shockwave Player
Used for 3d animations and games
Cortona
Used for viewing and interacting with virtual environments
Acrobat
The reader is needed to look at PDF files
QuickTime
QuickTime - often used for high quality video (preferred on Macs)
Windows Media Player
Microsoft's media player - plays sound and video
iPIX
Used for viewing 3D Picture Bubbles
Once installed, often you will have to restart your browser or even your operating system to make a plug-in active.
Generally plug-ins will be free but occasionally a company will ask for a fee for a more sophisticated version.
As a casual individual user you should never need to buy these jazzy versions: the free versions will do everything you want.
Finally, a tip: if you get bored waiting for big files to download over your creaky modem at home or are worried about the size of your phone bill, try looking through the internet magazines in your local newsagents.
Most of them have cover-mounted CD-Roms carrying up-to-date versions of all the most used plug-ins, so for a couple of quid you can install them in an instant, and swap your free disks with you friends!