My Mac has 10.5.8. I can no longer sync my iphone. What do I need to do?

Hi, did you update the iPhone to iOS7?

If so you'll need to upgrade the OSX on your Mac, if that's even possible...

So we know more about it...

At the Apple Icon at top left>About this Mac, then click on More Info, then click on Hardware> and report this upto but not including the Serial#...

Hardware Overview:

Model Name: iMac

Model Identifier: iMac7,1

Processor Name: Intel Core 2 Duo

Processor Speed: 2.4 GHz

Number Of Processors: 1

Total Number Of Cores: 2

L2 Cache: 4 MB

Memory: 6 GB

Bus Speed: 800 MHz

Boot ROM Version: IM71.007A.B03

SMC Version (system): 1.21f4

You need to be able to run Snow Leopard 10.6.8 in order to update iTunes and be able to sync with your iPhone.

If you can't run Snow Leopard you can't sync your iPhone.

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

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.