What is so wrong about 3. Bc4 ????

What is black's response to this supposed "blunder"? 

It's not a blunder, but there's two main problems, depending on how white continues.

-Generally people who play Bc4 intend to follow up with d3 and 0-0 and so on. The problem here is that black can play e6 with an eventual d5 and expand in the centre with tempo, the resulting positions tend to equalise for him or be slightly better due to his centre control and easy piece development.

-If white continues with d4 into an open sicilian they have given away a large number of possibilities by commiting their bishop prematurely to c4, whilst not really gaining anything as far as I can see.

I just drop ...e6 on the board and say "new idea, please" - attacking f7 is cool, but does it lead anywhere? Personally, I think it's great when people play Bc4 super early - for all of the reasons described above. You just kick it around (trap it if white isn't paying attention) and continue with the plan. Also, since black is forever questing for ...d5 and ...b5 in the Sicilian, it seems a shame to offer those moves with tempo.

If you'd like to hack like a crazy person and checkmate black immediately, why not this kind of thing: 

You're announcing to black that this is not playtime - black wants to be slow about things, you say "hulk smash" (in fact you can even play Bc4 in *THIS* position - Bobby Fischer did it regularly). With the really early Bc4, you say "I attack f7, you die" and black says "nope".....it's like 2.Qf3 - it pretends to be scary but actually creates no real threat. 

It's not terrible but it's not good either.

Godlike, so e6/d5 is a typical response to the weak bc4 ?  This doesn't seem bad at all for white...  I still don't see the downside.

What is the main line instead of 3. Bc4 ?

3. d4.

Blacks play there was rather poor. Black isn't going to play e6 d5 straight away, but will finish developing and play it later, and even in your diagram black would not take with the queen.

-It should also be noted that against all of blacks common second moves, Bc4 is probably least worst against ..d6, because at least this way black will lose a tempo with an eventual e6-d5. Againt 2..Nc6, e6 or g6 it is much worse because black will be saving this extra tempo with an e6-d5 at some point.

The main line is 3.d4 called the open sicilian where white will organise an attac based on their space advantage and easier piece development.

All that said, I should repeat that it's still entirely playable, but white just can't expect any real advantage from it. 

There are many variations in the Sicilian, but most games white's first 4 moves are the same.  1.e4 / 2.Nf3 / 3.d4 / 4.Nxd4

Here's an overview of many different variations:

http://en.wikipedia.org/wiki/Sicilian_Defence

GM Christian Bauer devotes to that line some 40 pages in "Experts on the Anti-Sicilian". Just get the book, and find out yourself.

It doesn't take a book to show Bc4 is worthless.

Thats the Fischer/Sozin right? 

If you are triing to avoid the normal sicilian lines, could i suggest you to look at the alapin variation?

To understand the alapin, you have to understand what black is triing to do with 1..c5.

Black want to trade his "c" pawn for your "d" pawn to get the pawn majority in the center.

White can accept that and play the normal sicilian, but you are going exactly where black want, so its safe to assume that he is well prepared there.

You can accept that hoping that you are more prepared than him or try to "deviate". The 2. c3 idea its a good deviation and often make sicilian player quite angry, because if black continues the "normal way" it will happen exactly the opposite as they wanted.

White will get a storng center, so the game contines following different paths.

Obviously a well prepared sicilian player should know how to meet also this variation ( as well as the rossolimo and the smith-morra). Black have still chanches to equalize, but in this case you are bringing him where you want instead of the opposite.

I always sugegst this line for white, because sicilian have toons of variations, so you willmeet naidorf, paulsen, dragon ( accelerated or not) variation ( among others), so you should know how to reply to all of them or learn just the alapin and force him to play the variation you know.

Just 2 cents from a sicilian player. ;-)

It isn't.

nothing is