Installing Nexista is actually much easier than one might think. All you have to do is "include" it in a script!
Nexista PEAR Install
pear channel-discover pear.nexista.org pear install channel://pear.nexista.org/nexista-0.2.4
The current release of nexista (as of December 2008) is 0.2.4. As new releases are published, the version number will change.