Here is a URL:
http://www.mysite.com?something=23&another=55
Is there a function that can strip everthing after the question mark?
Depends what you mean... are you wanting to use what's after the '?' or simply get rid of it?
If you simply want to get rid of it:
$url = preg_replace('/\?.*/', '', $url);
If you actually want to use it, look at [man]parse_url/man.