Casino Resources
I think that if you intend to win at any of the games offered by any casino, browsing the pages at The Wizard of Odds is something you should consider. He's a total math guy, so there are lots of odds and percentages, mixed in with "optimal strategies". And, even if that stuff doesn't completely appeal to you, there's plain English on the pages as well.

"Browser Based" is another way to say "No Download" when you're talking about online casinos. Although I've given my opinions on several casinos that I feel are the best of their respective group (microgaming, playtech, etc.), there are probably hundreds of different online casinos out there that accept Mac players. I just haven't had experience with them.

But, in case you're interested in trying out something that's not part of my beaten path, you can look over the list of browser based casinos at DMOZ.

Mac Resources
In case you're looking for a non-casino program for a Mac, here is a warehouse of mac computer links that can help.

And of course, I have to include a link to the mother of all Macs, Apple Computers. By the way, let me take a moment to tip my cap to the inspirational character that is Steve Wozniak!