There you go, PKGBUILDs for PHT are now in good shape and unofficial builds are rolling out!
plex-home-theater is available in the official [community] repository.
There is also a git package in the AUR, nightly builds for this one are available in the unofficial repository below. Unofficial repository
Add the following lines above official repos in '/etc/pacman.conf'.
SigLevel = Optional
Server = http://pkgbuild.com/~alucryd/$repo/$arch
Edit: Nuked the git package, github is only updated all at once when there's a release, making it useless.