If you are not on Lion but you are using a me.com address or a mac.com address, you still need to move your account. That way, you can continue to receive your mail in any email program (Mail.app, Entourage, Eudora, etc.). You don't get any of the other iCloud services, but you do keep your email address.
To get there you need to access http://www.me.com/move/ and follow the instructions.
I could not verify the steps exactly myself because I already did the move when I went to Lion. But according to the Mac Power Users podcast, this is where you go to do it. You must do this by the end of the month to keep receiving your mail.
If you are already on Lion, all you need to do is make the update in System Preferences, iCloud. Most of you did this already as part of the Lion setup.
The Thunderport Fiasco
Remember earlier this month when Apple issued an update to the software for the Thunderbolt Port? Killed a lot of Macs, which required reinstalling Lion. Well, Apple has finally re-released the update and the problem has been fixed. There is only one reason to get it, though, and that is if you want to use your Thunderport with Apple's new adapters for FireWire and wired Ethernet. If you don't, then the update is superfluous.
For those of you who are unfamiliar with this port, it's in all laptops issued since the late 2011 models, and the Mini. Older Macs have the DisplayPort which can be used only for external displays, and previous-to-2009 Macs had the mini-DVI port for that.
That port will be really useful once more devices that use it become available. So far, only a drive from LaCie and Apple's current 27" display use that port.