"Almost in all the projects which have done this thing, the micro is connected to a web server thru a LAN interface and actual web communication is done by the web server PC. "

No, the micro is the webserver; it is actually serving-up the pages!

"...but my objective is to connect the micro 8052 directly to the ISP"

That's the beauty of TCP/IP: once you've got your webserver & TCP/IP stack working, it makes no difference whether the actual physical link is Ethernet, ISDN, POTS, GPRS, etc, etc,...