Check for existing remote files

[mignev]

Hi guys. May be my question will break your nerves but please forgive
me. At first I love Nginx. Nginx is dream come true for poor student
like me :)) which doesn't have money for sloooooowly web servers for my
projects :)). So, BIG thanks for Igor and all of you guys who contribute
beautiful code for this project. You are awesome!

However, my question ofcource :) Can you tell me guys how I can check
for existing remote file. 
What i mean:
how can i check http://www.google.com/logo.png or
http://dl.dropbox.com/u/3720261/testdir/file.zip

10x in advance.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,165799,165799#msg-165799