how to install PHP4 and PHP5 (linux fedora4) ?

[_andrea.l]

I'd like to use php5 but at my work we use PHP4.
How can use both togheter?
I work whith Linux Fedora 4 then I have PHP5 installed
so how can install PHP4 and use PHP5 for my experiment and PHP4 for works?
Thank you in advance,
Andrea.