Here's what I've come up with (lately):
The first "label" sets the VISUAL (not volume) identifier; purely for your eyeballs! Kinda cute...
The "open" says what to do if you DOUBLE CLICK the disk icon from "my computer".
The "action" is what to do (when double clicked).
"Icon" is simply the icon to display next to the drive (in "my computer"). It can be something like ".exe[,x]" where ",x" is (optional) the (embedded) icon (in the program) in the program or an actual (as in my case) ".ico" file (yes, I stole one off the web).
Lastly, the "useautoplay" forces the system (WinXP or later) to actually list the default action to perform (or to run it, depending on your autorun settings).
NOTE: these settings are for WinXP or later, not for Win2K3 or earlier.
The remaining items are paired "shell" options. They cause the first item to be listed, the second item to execute (when you click on it). When you open "my computer" and you see your flash (or other removealbe drive) and you RIGHT CLICK on it, you will see these items listed as actions to perform.
NOTE: the action "shell" commands do NOT list the drive or path specifier! All references are from the (assumes/default) root of the device itself!
So, for my flash drive, I have the option to run Rainlendar (default choice) or to right click the drive itself and select to install various things or to take various actions (like shutdown, display uptime).
I hope this helps! I spent a couple of days researching this. The autorun.inf file is not very complicated. It was origianlly intended for CD, not flash drives. But WinXP (or later) can be made to do things for you, too.
label=my xxx Drive
action=Run Rainlendar 2
shell\Rainlendar=run Rainlendar 2
shell\insGTK=Install GTK for GIMP
shell\insTVNC=Install Tight VNC
shell\insUVNC=Install Ultra VNC
shell\xpsp3=Install XP SP3
shell\timeup=show uptime for this PC
shell\turnoff\=shut-down this PC
shell\rebooter=re-boot this PC
shell\powerUI=setup Tweak UI for XP
shell\powerCALC=setup Power Calculator for XP