I am running 10.5.8 can I upgrade to Lion? if not how do upgrade to 10.6?

First you need to check that your current Mac meets the System Requirements for Both Snow Leopard and Lion...

Snow Leopard Specs:

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

Lion Specs:

http://www.apple.com/macosx/specs.html

If it does... then you need to Purchase and Install Snow Leopard Disc,

Mac OS X 10.6 Snow Leopard

And then Purchase and Install Lion...

http://www.apple.com/macosx/how-to-buy/

Would Also Recommend that you do a Bootable Clone Backup of your current Hard Drive Before attempting any Major Upgrade...

By far the easiest way to make a Backup, is to use something like

SuperDuper http://www.shirt-pocket.com/

or CCC http://www.bombich.com/

Also... For Lion... Check the Compatibility of Third Party Applications you may be using...

See Here:

http://roaringapps.com/apps:table

There is no upgrade path.

You need to purchase Lion.

Once you have SL 10 6 8 installed you can use the App Store to get Lion - Providing your Mac meets the System requirements - .

Will also draw your attention to this link again...

For Lion... Check the Compatibility of Third Party Applications you may be using...

See Here:

http://roaringapps.com/apps:table

You're Welcome 🙂