is there any way to download diablo 2 on a mac pro with 10.6 or higher?, is there any way to download diablo 2 on a mac pro with 10.6 or higher?

Have you checked on the website of the Diablo 2 developer? This is a user to user tech support site for Apple products. Their website lists the requirements as being 10.3.9 to 10.6.8, which sounds like it fits in with your specs.

If you have previously registered your game with Blizzard then you can download the full installer from battle.net

1. Log in with your Battle.Net credentials
2. Go to "Account"
3. Select "Diablo II" under the Classics header
4. Select "Install OSX" to download the installer

As Barney mentioned, since the game is of the PPC variety, it will only run on 10.6.8 or lower.