I have a Mac OS X 10.5.8 how do I upgrade to OS X 10.6?
How do I upgrade to a OS X 10.6 / so as to upgrade to Lion?
I currently have a MacBook Pro OS X 10.5
MacBook Pro, Mac OS X (10.5.8)
You can purchase Snow Leopard Mac OS X 10.6 Snow Leopard - Apple Store
Make sure your Mac meets Lion's requirements > OS X Lion - Technical specifications
Once you have Snow Leopard installed you can download and install Lion from the Mac App Store.
Informative article to read BEFORE upgrading to Lion > Lion upgrade questions and answers: Apple Support Communities