After updating to Android 2.3, the radio keeps running in the background
Firmware is a bit of a loose term.  With Android you can assume that all firmware updates are Android updates, even if it's only a minor version update.  It's rare that a new bootloader or something would be pushed out with no changes to the OS.

Anyways, Android has lots of services running in the background all the time.  Unless it's consuming your battery &mdash; it's probably idle and not using any &mdash; it's not a problem.  Running task killers is a great way to make your battery life worse and destabilize your phone, so definitely don't do that.

Finally, Android is customized to varying extent by the manufacturers.  Most of them at least change the launcher, which can make the homescreen look different.  The fact that it looks different from the stock Android homescreen isn't surprising :)