Did Peter Parker invent the web-goo himself, or is it implied that he stole the formula from Oscorp? I'm a bit hazy on this.
In the film it appears that he orders the webbing from Oscorp. However later in the film he does say that he invented the formula himself (IIRC talking to Gwen, so he could be trying to impress her).
Speculation: I think Parker followed the age old scientific trick of starting with a known base (Oscorp's formula) and improving upon it thus allowing for a more web like shot.
From the comics universe spider-man actually does invent the webbing himself.