Not to second guess your calls, but Ubunto is primarily aimed at the desktop market. Servers are usually either a RHEL derivitive, or SUSE. I'd personally recommend getting yourself an CentOS5 disk, and use that. The basic Linux things are obviously fundamental, but you might as well learn the tools that you'll find in most corporations.
Rather than give tutorials on specific things, I'll just list off some areas you should research. If you don't know
man already, make a note of it. It's far more useful than Window's help files, and is every Linux SysAdmin's best friend. (Type
man <command> with everything I mention here) Google can also help a ton. I realize this isn't the tutorials you asked for, but I think it can help lay the Windows->Linux foundation that will make any LAMP tutorial much easier to use.
Services are controlled via scripts in /etc/init.d/. In RHEL,
chkconfig adds a management layer on top of that. Otherwise you need to use
/etc/init.d/<scriptname> start|stop|restart|status. You'll want to use
top to manage running processes, like Windows' Task Manager. (Kill processes with
df helps determine what's mounted, and
du can be used to determine sizes of directories.
sysstat can help diagnose IO issues.
free can help you determine memory usage. (Note that Linux handles memory differently)
Program updates are done via
yum on RHEL, or
apt-get on Ubunto.
Important configuration files live in the /etc/ directory. These control service configuration like Windows' registry keys/GUIs do. Most services have a similarly named .conf file or directory there. (I usually do a
ls -ld /etc/*service* to find it) /etc/fstab defines what gets mounted at boot. You'll want to use
vi to edit text files. Ignore anyone who mentions