I have all my stuff on a PC (my files, game and such) but, I don't have internet connection on my PC. I therefor would use a flash drive to transport the data to my computer. The computer over at my friends is an imac that I wanT to transport my stuff from. Will it still work even though one computers an imac and ones a PC.

Yep, just copy the entire The Sims 2 folder. You can also just copy select folders within, like Downloads, or SavedSims, or Neighborhoods. And you are talking the user data and not game files right? Because the game has to be installed you can't just copy it to another computer.