Hi,
if you are using apache, I think you are much better of using apache's compression, as this will also compress static text files (css, js, html, etc) and it will keep your php-code clean.
See http://httpd.apache.org/docs/2.0/mod/mod_deflate.html for an excellent how to.
And for other webservers, I'm pretty sure they have equivalents.
Cheers, Ronald