Resource for older Mac games?

Hi, long time lurker first time poster

I got a macbook not long ago (unibody) and have since been throwing a few older games on for mucking about on when I am out and about, usually stuff that does not need a disc in like Diablo 2, Warcraft 3, Eschalon Book 1 etc...

I have since found out that some of my favourite PC games of old were ported to the mac, but I have no idea where to get them from, some of them pop up used on ebay or Amazon but I would prefer to be able to buy them via dowload.

I am in the UK and Direct 2 Drive here has a limited selection, the Apple store does not have much other than recent titles. I am after:

Ghost Recon, and xpac if possible
Baldurs Gate 2 and xpac
Neverwinter Nights and xpacs (I see HoTU made it across!)
XIII

Any clues?

Thanks in advance