These are Tyrian related websites. Email me if you think a site should be added to this list

Official Tyrian Repository
This is a site Jason Emery created which will house all kinds of Tyrian goodness.
DosBox homepage on Sourceforge
You may need this x86/DOS emulator to run Tyrian on new computers.
AdPlug homepage on Sourceforge
AdPlug is an Adlib sound player library. You can use it to play Tyrian's music in the original LDS format via Winamp. It comes with an Adlib emulator if your soundcard doesn't support Adlib.
Official Tyrian page at Epicgames.com - DEAD
Epic is Tyrian's former publisher. Their official page is no longer online but you can find a mirror of the early version here and the latest version here.
Symmetry Entertainment - DEAD
Tyrian's second publisher. They went broke so their main offices closed and they could no longer publish any games.
Official Tyrian Tech Support FAQ
Strangely this remains at Epicgames.com even though everything else is gone.
World Tree Games
Tyrian's developers.
Lost Garden
Homepage of Daniel Cook, Tyrian's artist.
Portfolio of Cayenne Mandua
Homepage of Cayenne Mandua (CyclopsX), Tyrian 2000's artist.
The official Tyrian webpage.
Tyrian at MobyGames.com
The Moby Games entries for Tyrian and Tyrian 2000.
SlightlyOddGuy's Music
This guy has done a remix of the Rock Garden song from Tyrian and put it on his page in MP3.
A cool site full of information on shmups for all platforms.