Just check at
http://sf.net/projects/phex to get the betas
Also you can download them from CVS (Concurrent Versioning System)
Here's an instruction, but please wait, till I have found a way to include the download of ants into the mix..
The cvs-versions are the cutting edge, so they are often hard on your computer, but you can see all the new features :-) (It's what I do)
Which system do you use?
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Just create a new folder on your mac named CVS (or anything similar, the phex folder will be inside)
Open your Terminal (util
type "cd " and drag and drop your folder on it
press ent
put the following string into the terminal
"cvs -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/phex login"
press ent
"cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/phex co phex"
press ent
If it doesn't work, register at sf.net and use your User name instead of "anonymous"
type "cdphex/build"
press ent
type "./compile"
press enter