| I suggest that you file an amended 1040X as quickly as possible. The reason being is that if the IRS determines that you have underreported the 1099-Misc income on your 2008 tax return, you would be subject to not only the additional tax but would be assessed underpayment penalties and interest on this additional liability.
If, however, you voluntarily file an amended tax return, there is a possibilty that the IRS would abate these underpayment penalties and perhaps not even charge you interest on the additional tax liabilities! | 
