I was playing Chess Titans (Level 3).I attacked figuring that after the exchange, black would be behind in development...I proceeded to win the game though I forgot to write down all my moves (D'oh). It would be of great help if you guys could tell me something I missed, or even if I was not the first to play this line.

6. Nxb5! 

Threatens a check with a discovered attack on the en prise queen. 

6. N x b5 ?!

is a dubious . After 6. N x b5 ?! black could reply with 6. .. c6 !

4 ... c6 looks strong.

I wonder why the computer didn't play 7.Na6 instead of 7.Kd7?

4. d4 is preferred over Bb5+ because of 4...c6 (instead of Bd7) and the Bishop loses time retreating. 

4. ...c6 is the answer, not 6. ...c6.

6. ...c6 doesn't do anything constructive, whereas 4. ...c6 wins a tempo.

Even if 4. ...Bd7, I'd recommend 5. ...c6 or 5. ...Nc6 instead of trading into a blunder.

Edit: 6. ...Nc6 also prevents white from the discovered attack.

Any player of the Black pieces who understands the defense would reply 4...c6, and your "aggressive response" simply loses a tempo compared to the mainline.

The only rated players I could find who played this line more than once were Marvin Woelk (762) and Marie Kristin Raulf (745), playing in the same "Under 10" tournament.

4.Bb5 is unusual.  Typical is Nf3 or d4.  Latest theory suggest White is better of waiting on d4.

5.Qh5 puts you in a pin...  Not something I would volunteer to do.  It is said that 80% of Master level games are decided by a pin.  They are very dangerous... best to avoid them.

Perfect move...

Instead of ...4.Bb7, play ...4.Nc6

then if the white queen goes Qh5, then Bd7 protects knight and if the white bishop moves, black wins the queen