Apple released OSX 10.8 “Mountain Lion” on July 25. It is available from the Apple App Store as a download for $19.95. When you purchase one Mountain Lion, you can install it on as many Macs as you own. (if you received a Mountain Lion upgrade free with the purchase of a new Mac after June 11 2012, then the free one is good only for that one machine. You would have to buy one retail download to cover any other machines)
If you have a lot of computers, or if you have a slow internet connection, you probably don’t want to download the whole installer on each machine. You can use a USB memory keychain drive of 8 GB or more as a installer.
Instructions for copying the Mountain Lion installer onto a USB key: http://gigaom.com/apple/quick-tip-create-a-usb-installer-for-mountain-lion/
Creating a bootable USB Key of 10.8 http://www.iclarified.com/entry/index.php?enid=23486
Do you want to install Mountain Lion at all?
If you have a mission-critical machine, or operate under tight deadlines, or use older software oe peripherals that does not have 10.8 updates available, you do not want to upgrade the operating system of your machine. 10.8 is a major change of operating system, especially if you are jumping from 10.6, and you can expect that some things will not work, some things will take a lot of time to sort out, and that you may be forced into buying upgrades.
Do the research first. Check with all of your important programs’ publishers and device (printer, scanner, etc) manufacturers for 10.8 compatibility, and secure the upgrades before starting.
What doesn’t work with Mountain Lion:
Any PowerPC application that relied on Rosetta for compatibility with the legacy code will not work on either 10.8 Mountain Lion or 10.7 Lion. If you rely on legacy applications, you will either have to stay with OSX 10.6.8 or set up a dual booting drive arrangement so you can choose to boot with 10.6. You can set up a dual boot system either by having two different hard drives, or by partitioning one hard drive into two partitions (NOTE: paritioning a drive will destroy all of the data and applications on it. Make and test a complete backup before proceeding.)
Setting up two partitions for dual booting http://osxdaily.com/2011/03/12/how-to-install-dual-boot-mac-os-x-10-7-lion-and-10-6-snow-leopard/
Reports from around the Web of applications that don’t work (yet) on 10.8
A good source for up to date ccompatibility information is Roaring Apps http://roaringapps.com/
|Application and version that doesn’t work||Version number required to work in 10.8|
|ACDSee Pro 1.9|
|Adobe Creative Suite apps CS5 and earlier (certain CS5 apps work, some with issues)||CS5.5 and above|
|ArchiCAD 15 and earlier||ArchiCAD 16|
|Artlantis Studio 4.1 and earlier|
|Assassin’s Creed II|
|AutoCAD 2012 for Mac and earlier||AutoCAD 2013 for Mac|
|Barcode Pro 6.15|
|Canon EOS Utility|
|Chessmaster 9000 1.1.3|
|Cisco VPN Client 4.9|
|Citrix ICA Clinet 10.00x|
|Corel Painter 12.0x|
|Filemaker Server v.11 and v.12|
|Garmin Map Update|
|Logitech Harmony Remote Software|
|MacTheRipper v.2.x||v. 4.x|
|Symantec PGP Desktop 10.x||Symantec PGP Compatibilty page|
|Vector Designer 1.7.0||Vector Designer 1.7.2 from the App Store|