I have basically added the games I have, using the actual installed Icon, not something just Made up. So As far as Making more Gaming Icon's are concerned, I sort of left that up to the end user. Otherwise I could spend the rest of my life making Icons from past games. If you Need help making an Icon Just let me know, Sorry for the delay'd responce. Didnt know I got Validated till just now.
Simple way to make the Icon. First, Do a Google for Icon Sucker. Download, Install. Run. You can point it to installed programs, and in many cases Uninstalled CD's of Programs. You then Suck the Icon out in a BMP format. I then Suggest reducing its size to 16x16 and saving as a gif. Thats about it.. The rest is in the code, which is very very very easy to replicate... Just remember 3 steps. Language, Field, Map.
Create the Language Entry so the words show up, Create the Field so it exists in the database, and Map it so phpbb knows where to put it. If you get confused, Look at the install file, and look at the other games listed. Look at the files they alter. Also look at the way things are displayed in the ACP of PCP. After a little looking it should all make sense.
For you Pro's out there, If you have the desire or means to make this a non-PCP integration, have at it.. As that will not be in my future at this time.