how do I spoof a get request

I have noticed that sometimes I cannot fopen($web_address,'r') or use any similar files if the web address contains a form get in it. (i.e. ends in a ?var1=xxx&var2=xxx...). I was wondering if there is any way to spoof a get request to a web address? I looked at fsockopen and think I need to look over the http specifications, but is there an easier way? Also, is there any easy way to spoof posting a form? Thanks in advance, Dan