Based on the official release last week of TeXLive 2008, a collection of texlive packages is now available in extra and replaces the obsolete tetex.
Some important points to note:
PLEASE READ THIS: http://wiki.archlinux.org/index.php/TeXLive
The installation now goes to /usr instead of /opt/texlive. Upon upgrading from the 2007 packages, you might encounter some error messages about binaries not found under /opt/texlive/bin: you can safely ignore them.
Instead of upgrading, I suggest you simply remove all your old texlive packages first, and then do a clean install under /usr.
For reasons of space and because life is too short, I decided not to provide the documentation. You can consult it online at http://tug.org/texlive/Contents/live/doc.html or on CTAN. Documentation packages might soon be made available on [community] though.