ipod icon not on desktop to eject

Do you mean the icon +on the Desktop+ is not there? Is it still listed in iTunes, under DEVICES? If so, you can eject it from there (click on the small eject button next to the iPod's name).

If you have the iPod setting for +Enable disk use+ (on the iPod's Summary tab) unchecked, the iPod will not appear on the Mac's Desktop, unless it is actively syncing at the moment.

Also, if you go to Finder preferences, there is an option to show (or not show) +CDs, DVDs, and iPods+ on the Desktop. If that got unchecked, the iPod will not appear on the Desktop.

Now, if the iPod screens says to not disconnect, yet the iPod does not appear anywhere on the computer... You should probably shut down the Mac. If the iPod screen changes, disconnect it. If the iPod screen remains the same, use the two-button reset to restart the iPod.

http://support.apple.com/kb/HT1320

Since the Mac is OFF, it should go to the main screen; then disconnect it.

If the Mac was actively syncing to the iPod when it was disconnected, there may data corruption on the iPod. If the iPod was just connected with not activity, it is probably OK.

If the iPod is not working reliably, you should to a Restore in iTunes on the iPod to erase the iPod and initialize the iPod's software. Erase means the iPod will be empty. Then, re-sync to the iTunes library to get the files back on it.