am I breaking any laws?

[kus9]

I recently set up a blog: http://www.bsong.com

I modified the Red Bull can in my banner and did a little article on Red Bull drinks and their caffeine content. Are there any legal implications of what I'm doing? Am I allowed to modify and use a picture of their can like that?

[Steelsun]

They can probably claim unauthorized trademark usage and dilution and a claim that it could be confused with an authorized/official site.

[johntabita]

It might fall under Fair Use as a parody. But Fair Use is not a right, it's a defense. What would most likely happen is that Red Bull, if they found out, will send you a cease and desist notice, meaning, "take it down or we will sue you." That's when you must decide whether to remove it or fight them in court using the Fair Use defense.