strings and conditionals..

hi, am new to PHP, trying to learn strings... I'm a bit mystifed about something.. how do you test for conditions in strings? for example, how would you do what in JavaScript (or Java) you do like this

if (email.indexOf('@') != -1) { // etc..

also how do you test for length of a string? I tried:

if (strlen($myName) == 7) {

but got error...

I have looked at sections dealing with conditionals in tutorials, but don't see examles of this (also don't see functions like indexOf(), etc.. under Strings here,

thank you very much..