Frank_Rizzo - 12:35 pm on May 4, 2010 (gmt 0)
webmin is a server admin panel. It allows you to administrate all aspects of a Linux server (servers, networking, hardware, logs, backups).
I have not used xampp (only the separate components of it). Googling xampp control panel linux indicates that there are some dedicated xampp control panels which you can use for starting / stopping xampp.
If you want to make administrating the whole server easier then webmin would be a better tool to use.