I entered the US on 7/31/07 on a L1 Visa. As Immigration Law allows, my salary will continue to be paid by the mother company in Italy.
My Italian CPA says that Italian law allows me not to pay tax if I spend more than 50% of a calendar year in another country as an immigrant or non-immigrant in lawful status, provided that the income comes from work done in the other country.
Therefore I am not going to pay tax in Italy for that income.
Should I pay income tax in the US? And just for the income I make from the company sponsoring my L1, or any other income (consulting work, property tax, etc)?
Thanks!

If your income is from US, you have to report your total income earned while you are in US.
You should submit a Non-Resident Tax Form i.e.. Form 1040 NR in order to pay all the income you have earned from US.

Go to Internal Revenue Service (http://www.irs.gov) to get more information.

Thanks! The income is coming from an Italian company in my Italian bank account. What do you mean by "income from US"? I guess it's the all point.