Hi I have been in the US since 20th January 2006 and am on the payroll of my company since July 2006 , for the purpose of filling Tax returns for the year 2006 , am I a resident Alien or a non-resident alien?

I assume you are on either an H-1 or H-1B visa. If so, WHEN did the visa go into effect?

Are you married?

Need these answer to formulate correct answer!

Am on L1 - effective since November 2005 and I am maried

You are considered a resident alien. You can file jointly with your wife (regardless of her visa status).