Here's some suggestion:
Good TCP/IP book
Good DNS Server book
MS Win2K server book
IIS Book
Redhat Admin book
Apache book
Samba book
Good Database book, maybe SQL or MySQL or Access
Some Perl knowledge
cgi & asp would be helpful
and of course Hardware book to troubleshoot your webserver
Lots of stuff to learn
I work in Webhosting co and these are my daily feed

I still have much to learn though.
eRr