[leslie.jones]

I take it this is xampp for Linux (as chmod/chown would be nonsensical on windows)

To find the user just issue, as root,

ps -aux | grep apache

Left hand column is user, you may have a couple running as root, but the majority will usually be running as 'nobody' or 'www-data'.

chown www-data:www-data

to change the user and group at the same time - you'll probably want to do the lot so:

chown -R www-data:www-data /path/to/directory/*

Or safer to do the directory itself, then cd in and issue:

chown -R www-data:www-data *