Can somebody show me some ideas with Petrov's defense?

Hm. What I described wasn't that disaster with Nxe5 Nxe4 (just 4. Qe2 is good) but:

And I agree, 3. Nxe5 Nxe4 isn't easily punishable if black knows what he's up to... even though it's so provocative.

What if you rearranged the back rank and played fischerrandom? Would that pattern work?

How is that playable for black? Where is the compensation for that pawn?
I would play this line in tournaments, if you say that it is playable then it must be, but I don't see the compensation for that pawn. 
It would be a big surprise for everyone :D  

I still would not use 3...Nxe4, but it is not refutable. How would you go about holding onto the pawn? Next time I get this position I might just give it back with 8. Nc3. Although Volkman has no problem drawing the endgame after 8...Qxe5 9. Qxe5 Nxe5 10. Bf4 f6 11. O-O-O Bd7 12. Nb5 Bxb5 13. Bxb5  c6 14. Ba4 Bc5 15. Rhe1 Rd8 16. Bxe5 Rxd1+ 17. Kxd1 fxe5 18. Rxe5 Be7 Rooks are still on, so I would play this against a club player since there are only two results possible, but it is hardly a refutation.  

The Theory is Big.  Get yourself a book.

This thread is (very) short on viable ideas for the Petroff, unfortunately.

I know, we have (1) the atrocious 1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4 4. Nxf7?? Qe7 5. Nxh8 Nc3+, (2) the Cochran Gambit, (3) A bunch of unannotated games, and (4) 1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4 4. Qe2 Qe7 5. Qxe4 d6 6. d4 dxe5 7. dxe5 Nc6, which has actually been played by titled players. If your opening book stopped at 7. dxe5 with the assessment White won a pawn, you might be a little pissed off at the author, but I would not take Black's position if I were you.

Actually there is only one and a half result possible... Black should hold this, unless he plays badly. Black's choice is at move ten, between 10...Bd6 (holds equal material, but gives white the bishop pair) and 10...f6 which aims directly for a pawn-down, opposite coloured bishop+rook endgame. Apparently Volkmann likes the latter, and I think he is right.

8.Bb5 Bd7 9.Nc3 Qb4 10.Qf4! (preventing long castling due to the pressure on f7) is quite troublesome for Black, but he can play either 10...a6 or 10...0-0-0 11.Bf4 Qb4! (now this is much better) when Volkmann (again) had no trouble against strong opposition.

You should revise Afromeev's games with quite a bit of suspicion. He has declared in the past he can even get his cat a rating around 2400.

http://susanpolgar.blogspot.gr/2007/07/story-worth-reading-by-gm-baburin-of.html

Well, to add to that list, there's also (5) 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. d4 d5 6. Bd3 the mainline, and (6) 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3 Nxc3 6. dxc3 where white has open lines and queenside castling in exchange for pawn structure. Just that the first few lines are more interesting to talk about so the discussion sort of went that way.

I guess that explains this one:

Sorry Remellion, I diden't see that you gave mainlines at some point.

The idea may be excellent, or rubbish. This opening is NOT a Petrov, though.

Oh, I thought the initial moves 1.e4 e5 2.Nf3 Nf6 would qualify...
I'm quite ignorant about book openings, so I don't really know.

I guess that the development of the pieces transposed into something else? Some sort of simetrical Berlin or Giuoco Piano? What would you say?

I just thought this was an interesting idea in development.

A Four Knights I think. 

I see. Thanks for clarifying.

My post doesn't belong here then.

Usually you get into the Four Knights by 1.e4 e5  2.Nf3 Nc6  3.Nc3 Nf6. After your opponent playing 3.Nc3 in your game you can remain at the Petrov with 3. ...Bb4.