Call to undefined function: mysql_foo()...

I'm having a strange problem. If I run any MySQL function, I get the error message "Call to undefined function: mysql_foo()". Why would I be getting this? I've checked php.ini to see if it has the extension=mysql.so line, and I've run a phpinfo() script which says PHP was compiled with MySQL and it does have a MySQL section. The strangest part is that I have a perfectly functional phpBB installation using a MySQL database. Am I missing something obvious? -- Adam Atlas "During my service in the United States Congress, I took the initiative in creating the Internet." - Al Gore, March 9, 1999: On CNN's Late Edition