Can I open any Facebook games/applications on the Samsung galaxy tab? Games/applications like farm villi, Poker etc will work properly in the tab.
The builtin browser will probably show you a touch-optimized version of Facebook. You can try to get rid of it by changing the user agent string. See this question for more info on that.
Edit: Also, if the games require click-and-drag, this won't work on a touch screen.
I tryed to use Facebook games with the built-in Browser and some other browsers like FF, Miren, etc... Sometimes they work in one Browser, sometimes not. This seems to be dependant of the game you want to play. It is to say that FF does not support Flash so far.
I had no problems playing Backyard Monsters in standard Browser until the last update of Backyard Monsters (except it had laggy graphics), now no installed Browser works.
FreeFarmGame is running in Miren only.
Not tested any other so far, that are the only games I play.