URL vars in URL var?

I'm trying to pass a URL as a var in a URL: The url var should equal: http://www.someothersite.com/index.php?something=something&x=100&y=200 And I'm passing it to this URL: http://www.somesite.com/index.php?var=val So if I use: http://www.somesite.com/index.php?var=val&url=http://www.someothersite.com/i ndex.php?something=something&x=100&y=200 The problem is, if I echo $url; I get the following: http://www.someothersite.com/index.php?something=something So the vars after the & in the url var are being truncated, I'm assuming that they are treated as vars of the main URL. Any help appreciated, Shawn