Although I think Led Zeppelin is amazing Guitartricks can't just put up a song tutorial for it. The problem is that even teaching those songs (and the TABS for it) are copyrighted. For that Guitartricks needs to work with some record companies allowing them to teach some of the songs. Guitartricks, in return, needs to pay for being able to teach those songs legally.
Don't know which record companies GT is currently working with but maybe in the future, if GT is working with the right ones, we can see some Led Zeppelin lessons, because they are really great.
Perhaps an Jimmy Page / Led Zeppelin artists series would be great here on GT.
Also for future song-requests I suggest you use the Song-Request forumpage that is specifically for that: http://www.guitartricks.com/forum/forumdisplay.php?f=58
Best of luck.
JJ