d4xe5
Philidor Counter Gambit
The book way to a white advantage here is 4. de fe 5. Ng5 d5 6. e6 Nh6 7. Nc3 c6? (...Bc5 meets the same reply) 8. Ngxe5! de 9. Qh5+ g6 10. Qe5 Rg8 11. Bg5 when white should regain the piece and emerge a pawn ahead (11...Bg7 12. e7!)
I've played it before myself on occasion and when I have, I've ventured into the craziness of 6....Nf6 7. Nf7 Qe7 8. Nxh8 Bxe6 9. Be2 g6 10. O-O Nc6 and 11....O-O-O. Black is exchange down but will get an opportunity to go after the white king.

I see no "counter"-gambit, let alone a "counter counter"-gambit. Just looks like a regular gambit to me.

Yes, Philidor's idea had been an early ...f5, but 3.d4 f5 is the big problem with this. It is quite easy for white to achieve an advantage as black's position becomes a bit too loose.

i played the black side of this plenty of times in my learning chess plase. Its cute and can be great if white plays wrong but its not sound...if white plays correctly then black just has a miserable game. Id recommend this stuff for white:
You played it plenty of times in otb tournament games ?

check this out: http://blog.chess.com/JimWest?keyword=philidor !
Thanks Erik. The video quality is poor, but the content of West's lectures was well-worth my time.

Even though it allows what white wants, I believe exf5 is the strongest response. Many masters recommend 4.Nc3, but I dont think its so clear after say 4...fxe4 5.Nxe4 d5 6.Neg5 exd4 7.Nxd4 Nf6...... the move 6...exd4 is not mentioned in any book expect John Shaws book on 1.e4 and he says that after 6...exd4 blacks position looks ridicolous, but he does not continue further analysis in his book.... and I analysed that and black might be slightly worse, but definitely playable position.
What is your opinion on the philidor counter counter gambit?
It is very tactical and if either side makes a mistake, they lose. What do you think is the best line for white to play?