Update for OS X version not showing ...
My mac is not showing an update for a newer OS X version. I currently have 10.5.8 and need at least 10.6 to download other applications
Mac OS X (10.5.8)
10.6 is not going to come as a software update. What you need is to upgrade your OS: http://store.apple.com/us/product/MC573Z/A - make sure your system meets system requirements.
good luck