If you're going to upgrade your Mac to OS X 10.8 Mountain Lion, then you're going to want to take a look at this article that will help you get ready for the upgrade...

Apple's Mountain Lion OS is now available for puchase for $19.99

Today is 25-Jul-12. Today is Mountain Lion Day; and millions of Mac users all over the globe have been patiently waiting for the OS to be released so they can download it and upgrade their supported Macto the new OS. That last link is especially important for new upgraders, as it contains all of Mountain Lion’s Technical Specification Requirements, like supported models, RAM, disk space, etc.

A couple-three points on general requirements:

1. If you aren’t running at least OS X 10.6.8 (the latest version of Snow Leopard) or later on your supported Mac, you’ll need to upgrade to it before upgrading to Mountain Lion. Users of Lion on supported Macs don’t need to worry about this point.
2. Apple says you need a minimum of 2GB of RAM to run Mountain Lion. 4GB is better, 8GB or more is the sweet spot.
3. Apple says you’ll need at least 8GB of available disk space. Mountain Lion is a 4.5GB download. It needs another 3.5GB of temp space to do the upgrade, and the upgrade file eats itself after it executes. Make sure you make a copy of it before it runs so you don’t have to download it again if needed.

Before you get started on your upgrade, you need to do a couple of important tasks. If you don’t do all of these, the world isn’t going to end. You’re still going to be able to upgrade; but if you don’t, and you run into trouble, you’re gonna wish you had. So, while they may make the task a bit longer, they’re probably the right thing to do.

1. Bandwidth – It’s going to take a while to download the installer. 4.5GB takes a good while to pull down even on a good day, but ba-zillions of peoples are going to want to download Mountain Lion all at the same time. The best time to download is likely overnight. So, you may want to wait…
   If you live in a bandwidth challenged area (like some rural area or back-40), you might want to make a trip to an Apple Store or a Starbucks or other free-Wi-Fi zone. Apple isn’t going to deliver a Mountain Lion installer on a USB stick, like it eventually did with Lion.
2. Backups – If you use Time Machine, make sure you have a good backup if you plan to restore applications, music or other content on clean install systems.
3. Backups – Make a system backup of your boot drive (if you have a Mac with more than one hard drive). Super Duper is my new favorite, and WILL save your bacon if you need to start the upgrade process over again.

Once you have everything ready to go and you start the upgrade, your biggest obstacle is going to be patience. The upgrade is going to take a while, likely 90 minutes or so from start to complete finish; and it will include three or more reboots, depending on your system. Give yourself something else to do and let the upgrade run its course. Rushing things is only going to frustrate you and jeopardize the integrity of your Mac later.