Hiya peepz.
Remember my last post in the YourGameFinds section?
The one where I told ya I went to this Retroshop to buy 2 NES controllers, but ended up buying some NES games as well.
Well I was wondering one thing.
They also had 2 versions of Punch-out for the NES.
1 was the normal Punch-out (just said Punch-out on the label), and had a price of €30,- CIB
the other one was a lose cart of "Mike Tyson's Punc-out" and also was €30,- (but it's just the cart)

Now I was wondering what the difference was?
Any difference ingame? or just the label?

Those two games are basically the same game with one very large difference.  Mike Tyson's Punch Out was released first.  After Mike Tyson lost his title and wasn't the champ anymore, Nintendo decided to drop Mike Tyson from the title, so they made up a ficticious character named Mr. Dream to replace Mike Tyson, and called the new game "Punch Out".  Punch Out was released later on in the NES lifespan, but the two games are pretty much exactly the same.

ok thanx for clearing that out.
So if I buy the Mike Tyson version I get to fight him, and if I buy the other one I get to fight Mr. Dream?

Pretty much.  If you had to choose one, I'd get Mike Tyson's Punch Out because it's the original, but they're both just as fun in terms of game play.

Edit: Here's a great Wikipedia article that should clear up any questions you ever had about the games:

http://en.wikipedia.org/wiki/Mike_Tyson's_Punch-Out!!

30 euros!?  What a ripoff..you can pick that game up in pawn shops and second hand stores for next to nothing.  It's a classic, but it isn't rare IMHO.  I've had at least 20 copies of each of those ;)