There is a list of new features by edition on Wikipedia: Adobe Photoshop version history - Wikipedia, the free encyclopedia
I don't know what version Ascension used, but I believe that CS3 was current when he made his satellite style tutorial. I don't know if he's upgraded since then.
I'm not sure what you mean by square markers. Do you mean a square brush? If so, the square brushes aren't in the default brushes list; you'll have to load them. Open the Brushes palette (F5) and click the little icon in the upper right of that window. It looks like a downward-facing triangle and four horizontal lines. In the list that appears, choose "Square brushes." It should be the fourth or fifth item from the bottom of the list. It will ask you if you want to replace your current brush set; if you click OK, your current brushes will vanish, and the square brushes will appear. If you instead click "Append," it will put the square brushes at the end of your current list of brushes.
Other ways to make a square marker would be to use the Shape tool in Rectangle mode, or fill a square selection with your desired color, or use the Type tool and a dingbats font that has such a symbol.