[PHP] looting SPECIFIC information from outside source of file?

yeah, title says it all i guess.

I have absolutly no idea what im doing but i figure im going to have to do something like this (even though i dont know the proper functions)

[FONT=verdana][SIZE=2][COLOR=#000000]1. read the file [/COLOR][/SIZE][/FONT]
[SIZE=2][FONT=verdana][COLOR=#000000]2. create a function to find the parts of the file i want [/COLOR][/FONT][/SIZE]
[SIZE=2][FONT=verdana][COLOR=#000000]example of this: [/COLOR][/FONT][/SIZE]

GET TEXT after... 
"<div class="f"><span class="iesucks">&nbsp;</span></div> 

and stop at getting text at "<div style="margin-top:20px; border-top:1px solid #CCC; padding-top:10px;">" 

[FONT=verdana][SIZE=2][COLOR=#000000]pretty complicated for me, i have no idea where to start but heres what i have so far (all it does is read the fileā€¦) [/COLOR][/SIZE][/FONT]

$artist = urlencode($_GET['artist']); 
$url = 'http://www.last.fm/music/'.$artist.'/+wiki';