$read works only on local files, there's no builtin command that lets you read stuff from web pages. Using sockets is possible, but requires a near perfect understanding of sockets, the http protocol, connections, TCP/IP and a decent knowledge and experience in mIRC scripting and it's limitations. Oh, and lots of time too. All needed documentation can be found on the web, but think about wether it's worth the effort.
Maybe it's simpler to just manually save the page to disk, or use wget in your script to download the page for you. Also remember that lines on webpages are NOT lines in the source html file. An entire web page can fit on one line, meaning that $read will fail with a 'line too long' error since mIRC can only handle a bit more that 900 characters without resorting to &binvars.
