This is a problem that seems to have been reported a few times, but gets shot down each time as "NOT A BUG... blah blah," but it still doesn't work:

When running php3 w/Apache and attempting to run mysql function: mysql_connect, the following is returned as an error:

Fatal error: Call to unsupported or undefined function mysql_connect() in f:\html\test.php3 on line 13

Now, the general response to this problem is:
"Mysql support is not compiled in php win32", and
to use: "extension=php3_mysql.dll" in php3.ini or
dl() function.

The reality of the situation is that I have
extension=php3_mysql.dll
in my php3.ini, and it still doesn't solve that problem.
extension=php3_calendar.dll 
works just fine, and Calendar extension shows up in phpinfo(); but Mysql doesn't show up there.

When using dl("php3_mysql.dll");
the following error is returned:
Fatal error: Unable to load dynamic library 'C:/php3/php3_mysql.dll'
One of the library files needed to run this application cannot be found. in f:\html\test.php3 on line 11

And yes, php3_mysql.dll is located in C:\php3.