What is the most dangerous line after 5...bc5?What should white play?

d4.

5...Bc5 isn't a good move IMO, just allows white to get another tempo on the bishop from playing a move he wants to anyway.

What I have to do after 7...bb4+ 8.kf1?

If black takes your pawn, you will have a strong attack.

http://www.chess.com/games/view?id=120472

Strong attack?

Qb3, Nxc3, white has a strong development advantage/initiative.

1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 Bxb4 5. c3 Bc5 6. d4 exd4 7. O-O dxc3.How to reply?

Thank you so much

If you don't want to give black that option, you can castle on move 6?

simply take with your knight

Is that a good choice for tournament? 

What is the main play after 8.kf1?

Bb3 and you've gotten a pawn back.

Any dangerous threats?

After 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 Bxb4 5. c3 Bc5 6. d4 exd4 7.cxd4 bb4+ 8.kf1,give me a guide.

Is 7. 0-0 dc3: the good reaction of black? He has two pawns more, but lacks development. Is 7. ... Ne7 not a better answer for black? If white is not fast enough, then will black castle too.

7. 0-0 Ne7 8. cd4: Bb4 9. Qb3 0-0 10. Bf7:+ Rf7: 11. Ng5 Qf8.

Don't know if black will hold this, but it looks more logical then capturing another pawn, isn't it?