Find In String - HELP PLEASE

[Kamu]

hi
I need to find out how to find something in a string.
eg.
$fred = "cheese bill green"

If "cheese" is in $fred then do something..

basicly, the InStr function on Visual Basic.
thanks guys

[Kamu]

thanks to all you who helped me find out
function : strstr

[phpman]

strstr() is case-sensitive, use stristr() for case-insensitive