Upgrade my macbook version 10.5.8 to Mac OS X or 10.6?

Is there a way to upgrade my macbook version 10.5.8 to Mac OS X or 10.6?

Help! I used to be able to sync my music onto my phone but now I can't because a pop up always comes up saying "This installer requires Mac OS X version or 10.6 or later"

Also I just bought a printer and a pop up comes up saying "This HP software is not compatiblewith your versionof Mac OS X."