Hezbollah is in a world of hurt right now, so they are trying to make Israel make a mistake that would lead to a wider war (e.g. with Syria).
This would spread Israel thin and potentially relieve pressure on Hezbollah. This is also Al Qaeda's plan to save the mess (from their persepctive) left after we killed Zarqawi.
To those ends, Al Qaeda and Hezbollah are spreading rumors that would "implicate" Iran and Syria in the current war.
Of course, no Player is going to fall for such simple-minded tricks...but you can bet that the blogs and talking TV/radio heads and a few random posters will seize on whatever "Iran attacks" or "Syria declares war" sorts of rumors are being spread.
People hear what they want to believe, after all.
Do you have any data on how close Hezbollah and AQ are?
Why would Israeli officials make the same declarations against syria and iran?