I managed to fix the problem with my Acer Aspire One and nm-applet. I had update the Network Manager which had updated the “nm-applet”. It turns out that /usr/lib/pm-utils/sleep.d is in charge of closing down and restarting stuff during sleep. There is some code in the file 10NetworkManager that kills the applet and is then supposed to restart it. Something about the version of nm-applet that ships with the Aspire One is different to the one in NetworkManager-gnome-0.7.0-0.12.svn4326.fc8
So to fix the problem you can refer to the Acer Aspire One forum post or follow these simple instructions:
$ sudo sed 's/kill/# kill/' -i /usr/lib/pm-utils/sleep.d/10NetworkManager
This basically puts a # on the lines that kill the nm-applet and this stops the sleep from killing them. The suggestion I read was that the nm-applet written by Acer would ignore these kill signals but the fc8 version does not.