Q: I currently have OS X version 10.5.8 what is my next upgrade?

If you have a PPC iMac 10.5.8 is as far as you can do. If you have an Intel iMac:

Start by checking if you can run Snow Leopard:

Requirements for OS X 10.6 'Snow Leopard'

http://support.apple.com/kb/SP575

The OS 10.6 Snow Leopard install DVD is available for $19.99 from the Apple Store:

http://store.apple.com/us/product/MC573/mac-os-x-106-snow-leopard

and in the UK:

http://store.apple.com/uk/product/MC573/mac-os-x-106-snow-leopard

but nobody knows for how long it will be available.

When you have installed it, run Software Update to download and install the latest updates for Snow Leopard to bring it up to 10.6.8, or download the combo update from here:

http://support.apple.com/kb/DL1399

Check via Software Update whether further updates are required.

You should now see the App Store icon in iTunes, and you now need to set up your account:

http://support.apple.com/kb/HT4479

To use iCloud you have to upgrade at least to Lion, but some functions are only available in Mountain Lion:

http://support.apple.com/kb/HT4759

You can also purchase the code to use to download Lion (Lion requires an Intel-based Mac with a Core 2 Duo, i3, i5, i7 or Xeon processor and 2GB of RAM, running the latest version of Snow Leopard), or you can purchase Mountain Lion from the App Store - if you can run that:

http://www.apple.com/osx/specs/

Choose About this Mac from the Apple menu and check the processor.

If it's a PowerPC Mac, it's already running the newest OS it can.

If it's an Intel Mac, click here, install the DVD, and run Software Update.

(89401)

OS X 10.4/10.5 need to upgrade, 10.6.8 ok still

WARNING!

Upgrading OS X to 10.7-10.8 will not allow running of older PPC based programs you likely have installed.

You might decide it's best to buy a new machine and all new software for it rather than all new software for 10.7-10.8 on a older machine with slower processors/memory/graphics.

Snow Leopard (10.6) will run older PPC programs as it has Rosetta.

10.6.8 max is likely the best you can do performance wise on that older machine.

Make sure you backup a copy of your users files off the machine to a external storage drive BEFORE upgrading as it can go bad and require a wipe and install to fix it.