You may want to check out <A HREF="http://www.anandtech.com/cpu/showdoc.html?i=1927" target="_new">this</A> review to find out yourself. But those guys who replied here earlier should be about right. In the review that I gave you, the Athlon XP 1700+ (1466MHz) is ahead of the Celeron 2.6GHz by a huge margin, so I believe a 1.1~1.2GHz Athlon should match a Celeron 2500 in performance for gaming.
Celerons are for people who don't know anything about computers except how to use a couple programs, and are unwilling to learn about them at all.
<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>